Untitled Flashcards Set

Learning Objectives
Chapter 12
1. Define the terms cephalic and cephalization.

-              Cephalic- relating to cranium or head

-              Cephalization- concentration of neural/sensory organs towards bodys anterior end(cranial): highest level is reached in human brain, results in complex neural system and intelligence

2. Recall general characteristics and surface anatomy of the brain (e.g., weight, size, etc.).

-              Appearance- mass of wrinkled, pinkish-gray tissue

-              Weight- 1450-1600g(3-3.5 lbs) 2% of total body weight

-              Size- body mass determines brain size

-              Surface anatomy: cerebral hemispheres(cerebrum), cerebellum, brain stem

3. Recall the 3 primary brain vesicles and be able to identify them by both their primary and secondary designations (e.g., prosencephalon or forebrain).

-              Prosencephalon(forebrain)

-              Mesencephalon(midbrain)

-              Rhombencephalon(hindbrain)

4. Recall the 5 secondary brain vesicles and indicate from which primary vesicle they are derived.

-              Prosencephalon- forebrain: telencephalon(tel=end) and diencephalon(di=double)

-              Mesencephalon- midbrain: mesencephalon(mes=middle)

-              Rhombencephalon – hindbrain: metencephalon(met=beyond) and myelencephalon(mye= spinal brain) 

5. Name the adult brain structures that are derived from each of the secondary vesicles.

-              Telencephalon: Cerebrum (cerebral cortex, basal ganglia, hippocampus)

-              Diencephalon: Thalamus, hypothalamus, epithalamus (including the pineal gland)

-              Mesencephalon: Midbrain (tectum and tegmentum)

-              Metencephalon: Pons and cerebellum

-              Myelencephalon: Medulla oblongata

6. List the adult neural canal regions from superior to inferior (vice versa).

-              Lateral ventricles

-              Third ventricle

-              Cerebral aqueduct

-              Fourth ventricle

-              Central canal

7. Describe how the midbrain and cervical flexures form.

-              Soft brain tissue grows faster than fetal skull, causing it to fold and allow hemispheres to grow posteriorly and laterally

8. Recall the purpose of brain surface convolutions and when they first appear.

-              Show by week 26, increases total brain surface area more neurons occupy limited space by -100 billion neurons

9. List the 4 major adult brain regions and associated structures.

-              Cerebral hemispheres- cerebrum

-              Diencephalon- thalamus, hypothalamus, epithalamus

-              Cerebrum

-              Brain stem- midbrain, pons, medulla

10. Differentiate between brain white and gray matters based on myelination and fiber length.

-              White matter- long, myelinated fibers arranged in tracts(bundles)

-              Gray matter- short, nonmyelinated fibers w/ associated neuron cell bodies(soma)

11. Distinguish between white/gray matter patterns in the cerebrum, cerebellum, brain stem and spinal cord regions.

-              Cerebrum/cerebellum- gray/white/gray

-              Brain stem- gray/white

-              Spinal cord- gray/white

12. Describe lateral ventricles, septum pellucidum, interventricular foramen, third ventricle, cerebral aqueduct, fourth ventricle, and lateral/median apertures. Locate each structure.

-              lateral ventricles - paired C-shaped cerebral structures separated medially by a thin membrane called septum pellucidum

both connected to 3rd ventricle via interventricular foramen (IVF)

-              third ventricle - middle ventricle located in the diencephalon

connected to the 4th ventricle via cerebral aqueduct

-              fourth ventricle - hindbrain location being dorsal to pons

CSF moves into external spaces brain/spinal cord via lateral/median apertures

13. State the purpose of the lateral and medial apertures.

-              Flow cerebrospinal fluid, nutrient delivery and waste removal

14. Differentiate between a gyrus, sulcus, and fissure.

-              Gyrus(gyri)- elevated ridge-like area(top of convulsion)

-              Sulcus(sulci)- shallow groove located between two gyri

-              Fissure- deep grove separating large brain areas

-              Longitudinal fissure- separates L/R cerebral hemispheres

-              Transverse cerebral fissure- separates cerebrum from cerebellum

15. Describe the 3 major regions of the cerebral hemispheres.

-              Cortex- superficial gray matter, provides cognitive function( neuron cell bodies, unmyelinated fibers, glial cells)

-              White matter- subcortical area, allows communication between cerebrum/cerebellum and lower CNS structures (myelinated fiber tracts(bundles)

-              Basal nuclei- organized subcortical gray matter areas, roles in motor control, attention, cognition (centers of activity lying deep within cerebral white matter)

16. Recall the locations of the major sulci and gyrus dividing the brain into various lobes.

-              Central sulcus- separates parietals/frontal lobe

-              Parieto-occipital sulcus- separates parietals/occipital lobe

-              Lateral sulcus- separates temporals from parietals/frontal lobe

17. Recall the locations and functions of the 5 brain lobes.

-              Frontal- cognitive function and motor movement

-              Parietal- integrates sensory information

-              Temporal- auditory processing/ long term memory

-              Occipital- visual processing

-              Insula- emotion, homeostasis regulation, gustation, pain

18. Discuss the location of the insula relative to the other 4 brain lobes.

-              Insula brain lobe is internal to other lobes, cannot be seen from surface(exception)- located deep to lateral sulcus

19. Discuss why the cerebral cortex is called the seat of the “conscious mind”.

-              Self-awareness- non emotional cognitive brain area: enables memory, perception, reasoning, communication, voluntary movements

20. Recall the functions and associated major sulci/gyri of cerebral cortex sensory, association, and motor areas.

21. Explain the cortical concepts of lateralization, cerebral dominance, and contralateral functioning.

Lateralization- one side specializes in a particular process

- Left hemisphere attributed w/ greater language abilities, math, logic skills

- Right hemisphere attributed w/ greater visual-spatial, emotion, artistic skills

Contralateral function- sensory/motor functions are controlled by opposite cerebral hemisphere

-                The left side controls right limbs: right side controls left limbs

Cerebral dominance- one hemisphere exercises more control over functions like language and handedness

 - Left-hemisphere dominant are usually right-handed (~90%)

- Right-hemisphere dominant are usually left-handed (~10%)

22. Describe the relationship between right/left-handedness and language.

- Cerebral dominance

- Left-hemisphere dominant are usually right-handed (~90%)

- Right-hemisphere dominant are usually left-handed (~10%)

23. Discuss the function of cerebral white matter tracts.

- Deep to cortical gray matter, contains 3 major fiber tracts: allows upper/lower cns structure communication

24. Describe commissural (corpus callosum), association, and projection fibers location and function.

- Association fibers- connects different areas in same hemisphere

- Commissural fibers- connects same area of different hemispheres: where they communicate and act as a whole

- Corpus callosum is a wide, flat bundle of commissural fibers

- Projection fibers- long sensory/motor fibers, joins cortex w/ lower brain/ spinal cord

- Corona radiata- terminal part of projection fibers in cerebral cortex (resembles a crown)

25. Describe cerebral basal nuclei structure and recall their general functions.

- 4 groups of subcortical gray matter deep to white matter of cerebral hemisphere

- Caudate nucleus, putamen, globus pallidus, substantia nigra

- Receives input, filters out incorrect/inappropriate responses, starts/stops monitors movement intensity

26. Describe location, important structures, and functions of diencephalon areas:
• Thalamus
• Hypothalamus
• Epithalamus

27. Describe location, important structures, and functions of brain stem areas:
• Midbrain
• Pons
• Medulla oblongata

28. Describe location, important structures, and functions of cerebellum.

Location- dorsal to pons and medulla, 11% of brain mass

Structure- central vermis(worm-like), pleat-like gyri called folia

-              Central white matter named arbor vitae(tree-like), cerebellar peduncles connecting cerebellum-brain stem

Functions(major role in motor movement)- provides precise timing/ correct muscle contraction pattern; plays a role in cognition(puzzle solving); ensures proper balance/posture- all activities occur subconsciously

-              G-W-G pattern

29. Explain cerebellar processing for “coordinated” motor activity.

-              Receiving Input: Integrates signals from the motor cortex, proprioceptors, vestibular system, and sensory organs.

-              Integration: Compares intended movements with actual movements to detect errors.

-              Coordination: Fine-tunes muscle actions for smooth, accurate, and balanced movements.

-              Feedback: Sends corrective signals to the motor cortex for real-time adjustments.

-              Learning: Stores procedural memories to improve motor skills over time.

30. Describe location, important structures, and functions of functional brain limbic and reticular formation systems.

Limbic System

• Location: Around the thalamus and upper brainstem.

• Key Structures: Hippocampus, amygdala, hypothalamus, cingulate gyrus, and fornix.

• Functions: Regulates emotions, memory, learning, motivation, and autonomic/endocrine responses.

Reticular Formation System

• Location: Core of the brainstem, from the medulla to the midbrain.

• Key Structures: Reticular Activating System (RAS), raphe nuclei, locus coeruleus, medullary reticular formation.

• Functions: Controls alertness, sleep-wake cycles, motor coordination, sensory modulation (e.g., pain), and vital autonomic functions like heart rate and respiration.

31. Describe 4 protective mechanisms of the brain.

Bone- prevent/reduce traumatic injury

Meninges- connective tissue membrane barriers

Cerebrospinal fluid(CSF)- buoyancy support

Blood-brain barrier- cellular/metabolic barrier altering brain capillary permeability

32. Describe the location, structure, and functions of the meninges.

Location- meninges lie between skull and cerebral gray matter cortex

Structure of 3 connective tissue membranes located external to both brain /spinal cord, includes dura, arachnoid, pia matters

Functions- cover/protect CNS structures, protect blood vessels/ enclose venous sinuses, contain cerebrospinal fluid(CSF), form partitions within the skull

33. Correctly order meningeal dura, arachnoid, and pia maters from superficial to deep and also from deep to superficial.

-              From superficial to deep:

Dura mater (outermost layer)

Arachnoid mater (middle layer)

Pia mater (innermost layer, adheres to the brain and spinal cord)

-              From deep to superficial:

Pia mater

Arachnoid mater

Dura mater

34. Define the terms dural venous sinuses, subdural space, subarachnoid space, arachnoid villi.

-              Dural venous sinuses- venous blood channels created by a separation of dural periosteal/meningeal layers

-              Subdural space- narrow space between dura matter and arachnoid membrane( site of subdural hematomas)

-              Subarachnoid space- wide area beneath arachnoid matter but above pia matter, filled with CSF

-              Arachnoid villi- finger-like projections of arachnoid matter extending into dural venous sinuses- return CSF to venous blood

35. Discuss the composition, location, and function of the dural septa (e.g., falx cerebri).

-              protective membranes extending inward to separate cerebral hemispheres/cerebellar lobes

 falx cerebri - deep into longitudinal fissure to corpus callosum

 tentorium cerebelli - extends into cerebellar transverse fissure

 falx cerebelli - runs along cerebellum vermis (midline)

36. Describe the relationship between pia mater and brain blood capillaries.

-  smaller blood arterioles/capillaries pass through pia matter to nourish brain, nutrients move from the blood into brain extracellular fluid

37. Describe the location, composition, and functions of cerebrospinal fluid (CSF).

-              Location- CSF circulates internally in brain ventricles and externally in subarachnoid space around the brain/ spinal cord

-              Composition- clear/colorless filtrate produced from blood plasma; less protein, 2/3 blood glucose, different ion concentrations than blood plasma

-              Functions-buoyancy- liquid cushion prevents the brain from crushing under its own weight, protection- shields against blows and other trauma, chemical stability- provides limited nutrients, optimal chemical signaling

38. Describe the location, structure, and function of choroid plexuses.

-              Specializes blood vessel network hanging from ventricle roof, forms CSF from blood plasma

-              Area is lined with ependymal calls w/ tight junctions all around

-              Porous pia mater capillaries leak blood plasma into interstitium

-              Processed by ependymal cells ion pumps, released into ventricles

-              Cells simultaneously remove some metabolic waste

39. Discuss the structure of the blood-brain barrier and how it functions. Recall what substances can or cannot pass through it.

-              Selective 3- layer composed of

1.        Capillary endotheliuym w/ tight junctions

2.        Thick basal lamina(basement membrane)

3.        Astrocyte feet contacting outer endothelium wall

-              Located in most brain areas but not in brain stem vomiting center and hypothalamus( areas analyzing blood chemistry)

-              Selective substance passage:

·      Restricts- microbes, red-blood cells, proteins, some toxins

·      Allows- O2/CO2, glucose, amino acids, fatty acids, lipids, WBC, anesthetics, alcohol

40. Recall 5 brain disorders and their associated defects.

1. traumatic head injuries - concussion, contusion, subdural or subarachnoid hemorrhages can result in brain damage

2. cerebral vascular accident (stroke) - brain tissue death as a result of blood supply interruption

3. Alzheimer’s disease - progressive degenerative disease leading to dementia (damages hippocampus)

4. Parkinson’s disease - substantia nigra dopamine-secreting neurons deteriorate causing loss of movement & tremors

5. Huntington’s disease - fatal autosomal dominant genetic disorder characterized by basal nuclei/cerebral cortex deterioration

41. Define the terms epidural space and lumbar puncture (LP). Recall the area where an LP is performed.

-              Epidural space- fat/vein-filled space between vertebrae/dura mater, site of epidural injections and lumbar puncture

-              Lumbar puncture(spinal tap)- needle is inserted between L4-L5 vertebrae, collect CSF in subarachnoid space

-              In and by the spinal cord

-              -17” long, ¾” diameter

42. Describe the location, functions, and major structures/landmarks of the spinal cord.

-              Long, thin tubular bundle of segmented nervous tissue*, extends from skull foramen magnum to L1-L2 vertebrae

-               provides two-way communication to the brain via projection fibers & initiates spinal reflexes

-               protected by bone, meninges, CSF (all external)

-              spinal nerves - 31 pairs, attached laterally to cord via L/R spinal roots

-              cervical/lumbar enlargements - bulging area of nerve bundles, serves upper/lower limbs

-              denticulate ligaments - saw-toothed pia mater secured to dura mater on adjacent vertebrae

-              conus medullaris - tapering terminal spinal cord portion, cord ends at L1 level

-              cauda equina - collection of nerve roots at inferior end of vertebral canal, L2-L5 area

-              filum terminale - fibrous extension of cone- shaped pia mater, anchors spinal cord to coccyx

43. Discuss the spinal cord organization into left/right parts, spinal nerves, spinal roots, rootlets, gray mater horns, and white matter tracts.

-              Exhibits a gray- white matter pattern from central cavity outwards

-              Incompletely divided into L/R halves

-              Gray commissure- interneurons running along either side of central canal connecting L/R halves across cord

-              Gray matter horns- butterfly(H) shaped later L/R gray matter masses enclosing central canal

·      Dorsal/ventral horns- found along entire cord length

·      Lateral horns- only found in thoracic/superior lumbar regions

-              Spinal nerves- paired, PNS mixed nerves on L/R halves

-              Dorsal root ganglion- swollen dorsal root area containing many unipolar sensory neuron cell bodies

-              Sensory (afferent inflow)- spinal nerve (PNS), dorsal root ganglion, dorsal root, dorsal rootlets, dorsal horn interneurons(CNS)

-              Motor (efferent outflow)- ventral horn interneurons (CNS), ventral rootlets, ventral roots, spinal nerve (PNS)

44. Define the term funiculus.

- a bundle of nerve fibers or axons that is enclosed by a tubular sheath

- In white matter region

45. Discuss how organization of spinal cord gray and white mater areas allows communication with each other and higher brain structures.

-              Gray matter- ventral/dorsal horns are CNS interneurons, interface w/ sensory or motor PNS neurons

·      Somatic/visceral sensory- afferent input via the dorsal root

·      Somatic/visceral motor- efferent output via ventral root

-              White matter- colums containing several tracts carry signals in ascending, descending, transverse directions

-              L/R side communication occurs via white directions

46. Discuss 4 generalizations of neural pathways.

-              Unidirectional Signal Transmission: Signals travel in one direction, with sensory (afferent) pathways sending input to the CNS and motor (efferent) pathways sending commands from the CNS to muscles or glands.

-              Specificity of Function: Pathways are specialized for particular functions, such as touch, pain, or temperature sensation.

-              Crossing (Decussation): Many pathways cross sides in the brainstem or spinal cord, allowing for hemispheric coordination and control.

-              Plasticity and Adaptability: Neural pathways adapt through plasticity, enabling learning, recovery from injury, and the formation of new connections.

47. Label the Study Figures for Chapter 12 posted @ Mastering A&P > Exam Materials > Study Figures.

Chapter 13
1. Describe the function, structural organization, and components of the PNS.

-              PNS - includes all neural structures mainly located outside of brain/spinal cord (CNS)- sensory and motor divisions

-              sensory receptors, peripheral nerves, associated ganglia, motor endings

-              PNS neurons directly interface w/ CNS neurons to provide essential links to-and-from environment

-              PNS & CNS function as a continuous unit, a two-way communication pathway

-               connect body walls, limbs, visceral organs to CNS control center

2. Differentiate between PNS sensory and motor pathways.

-              sensory - input pathway for detected stimuli

-              motor - output pathway for motor response, more complex since it involves 2 different motor subdivisions:

3. Describe characteristics of the 2 PNS motor subdivisions.

a.        somatic nervous system (SNS) - reacts to external stimulus causes a response involving voluntary (conscious) control; effector = skeletal muscle
b. autonomic nervous system (ANS) - deals with internal stimulus causing a response involving involuntary (unconscious) control; effectors = cardiac/smooth muscles, glands- sympathetic and parasympathetic division

4. Define the terms stimulus, sensory receptor, and receptor potential.

-              Specialized neural structures responding to a stimulus, a change that causes or incites receptor activity

-               activation results in localized depolarizations called receptor potentials

-               triggers impulses (AP) sent up PNS afferent pathway to CNS

-  Classification schemes:

1. stimulus type

2. location

3. structural complexity

5. Differentiate between sensory mechanoreceptor, thermoreceptor, photoreceptor, chemoreceptor, and nociceptor by stimulus type.

1.        mechanoreceptors - respond to changes in mechanical force (touch, pressure, vibration, stretch, itch)

2.        thermoreceptors - sensitive to temperature changes
3. photoreceptors - respond to light energy (e.g., retinal cells)
4. chemoreceptors - respond to different chemicals in solutions (e.g., smell, taste, changes in blood chemistry)
5. nociceptors - subtypes of mechanoreceptors, thermoreceptors, or chemoreceptors sensitive to pain-causing stimuli
-  overstimulation by excessive heat, cold, pressure, inflammatory mediators (chemicals)

6. Differentiate between an exteroceptor, interceptor, and proprioceptor based on location and function.

1. Exteroceptors - found near the body surface responding to stimuli
from outside of the body, including special sense organs
-  sensitive to touch, pressure, pain, temperature
2. Interoceptors - found in internal viscera, blood vessels
responding to stimuli from within the body
-  sensitive to chemical changes, stretch, and temperature changes
3. Proprioceptors* - found in skeletal muscles, tendons,
joints, ligaments, bone/muscle connective tissue
-  responds to organ degree of stretch (lengthening

7. Distinguish between simple and complex receptors based upon their locations.

-              sensory receptors are either simple or complex

-               simple receptors - modified dendritic ends of sensory neurons associated with general senses, covers most body regions

-               complex receptors - sensory neurons found only in special senses organs (e.g., retinal rods, olfactory filaments)

8. Describe unencapsulated and encapsulated simple sensory receptors.

- simple receptors are either unencapsulated or encapsulated
- Unencapsulated receptors - free fiber endings, found mostly in epithelium/connective tissue
- Encapsulated receptors - connective tissue covered fiber endings, body-wide distribution (mostly mechanoreceptors)

9. Recognize the location and stimulus of unencapsulated simple receptors including, free dendritic nerve endings, Merkel discs, and hair follicle receptors.

10. Recognize the location and stimulus of encapsulated simple receptors including, Meissner’s corpuscles, Pacinian corpuscles, Ruffini endings, muscle spindles, tendon organs, and joint kinesthetic receptors.

11. Describe the organization and function of the somatosensory system.

-              Somatosensory system - multipart sensory (input) system made up of PNS receptors & CNS processing centers

 detects external stimuli of thoracic/abdominal body walls, limbs

 does not involve internal organs (viscera)

 sensory input is received via several receptor types:

 exteroceptors, proprioceptors, interoceptors

 transmits several different types of sensation (e.g. touch, position,

pain)

12. Describe the 3 neural integration levels of the somatosensory system.

Stimulus must first excite receptor field of a sensory receptor,

3 different neural levels carry/process stimulus input

receptor level - sensory receptors transduce (convert) physical

energy into a nervous signal or graded potential

circuit level - ascending pathways* carry

sensory information to different brain areas

 thalamus, cerebellum, cerebrum

perceptual level - neuronal circuits in cerebral

cortex interpret (associate) multiple inputs

 identify/interpret sensations

13. Distinguish between sensation and perception.

The somatosensory cortex interprets physical sensation by an act of perception (impression)
§ An organism’s survival depends upon both active sensation detection & correct perception of a stimulus
1. sensation - conscious awareness (sense of a change) in either
internal or external environments, constant Objective trait = a painful stimulus either does or does not generate graded potential
2. perception - interpretation (translation) of a stimulus, varies Subjective trait = degree of pain “felt” by brain

14. Define the terms pain threshold, pain tolerance, and referred pain.

-              pain threshold - point at which a stimulus activates pain, same for everyone for a particular stimulus (e.g., temp, pressure)

-               pain tolerance - an individual's ability to withstand pain differs even though stimulus intensity is same

-               visceral pain - deep, aching, gnawing pain of vital organs located in thorax/abdominal cavity

-               referred pain - visceral organ pain is perceived at a location other than site of painful stimulus

15. Describe the components of a nerve.

-              Nerve - long cord-like PNS organ consisting of parallel bundles of many neuron fibers, feed by central artery/vein

-              size varies, either myelinated or unmyelinated, contain both sensory & motor neurons, enclosed by connective tissue layers

16. Differentiate between the 3 nerve connective tissue coverings by location, created divisions, and connective tissue type.

endoneurium - delicate, loose connective tissue sheath surrounding each axon
§ endoneurial fluid - low protein liquid similar to CSF in between endoneurium & axon*
2. perineurium - intermediate fibrous sheath separating nerve fascicles (fiber bundles)
3. epineurium - outer tough fibrous sheath surrounding all nerve fascicles
*Provides blood-nerve barrier (axons)

17. Describe direction of nerve impulse flow in sensory, motor, and mixed nerves.

Nerves are classified by direction of impulse conduction
1. mixed nerves - contain both sensory/motor fibers carrying impulses to & from CNS (most common type)
2. sensory nerves - only carry afferent impulses towards CNS
3. motor nerves - only carry efferent impulses away from CNS

18. Differentiate between cranial and spinal nerves by point of origin.

1.        spinal nerves - mixed nerves innervates most of body outside of head, interfaces w/ spinal cord
2. cranial nerves - sensory, motor, or
mixed, mostly innervates head, interfaces w/ brain (especially at brainstem)

19. Discuss the difference between CNS and PNS nerve repair.

Damage to mature, amitotic CNS neurons is serious since oligodendrocytes secrete growth-inhibiting proteins

20. Describe the PNS nerve repair process.

PNS neurons can be repaired if soma remains intact, involves a series of events to repair damaged area of a fiber
§ starts with a degeneration of damaged fiber ends & a “clean up”

21. Recall Roman numerals, names, functions, and general descriptions of the 12 cranial nerves.

Twelve cranial nerve pairs directly interface w/ parts of brain but are still PNS structures
§ 2 pairs arise from forebrain (CN I-II)
§ 10 pairs arise from brainstem (CN III-XII)

Filaments of olfactory nerve (I)- sensory function(smell)

Optic nerve (II)- sensory(vision)

Oculomotor nerve (III)- motor function; parasympathetic fibers

Trochlear nerve (IV)- motor function

Trigeminal nerve (V)- sensory(general sensation); motor function

Abducens nerve (VI)- motor function

Facial nerve (VII)- sensory(taste); motor function; PS fibers

Vestibulocochlear nerve (VIII)- sensory( hearing and balance); some motor function

Glossopharyngeal nerve (IX)- sensory(taste); motor function; PS fibers

Vagus nerve (X)- sensory (taste); motor function; PS fibers

Accessory nerve (XI)- motor function

Hypoglossal nerve (XII)- motor function

22. Describe naming conventions for spinal nerves and recall how many are associated with each vertebral region.

Thirty-one pairs of mixed nerves serving most of body
§ head/some neck areas are served mostly by cranial nerves
§ most spinal nerves leave its associated vertebra superiorly
§ Location:
§ cervical (C1-C8) - 8 pair
§ C7 leaves superiorly but C8 leaves inferiorly (exception to rule)
§ thoracic (T1-T12) - 12 pairs
§ lumbar (L1-L5) - 5 pairs
§ sacral (S1-S5) - 5 pairs
§ coccygeal (Co1) - 1 pair

23. Recall structural relationships between a spinal nerve, its medial roots (ventral and dorsal), their corresponding rootlets, and any associated root ganglia.

Medial roots (paired) - connect lateral spinal nerves to spinal cord, carry either sensory or motor information
§ dorsal roots (sensory input pathway) - spinal nerve → dorsal root ganglion → dorsal root → dorsal rootlets → dorsal horn
§ ventral roots (motor output pathway) - ventral horn → ventral rootlets → ventral root → spinal nerve

24. Define the term ramus and classify dorsal rami, ventral rami, and meningeal branch by locations served.

Rami - branches of spinal nerve formed from dorsal & ventral roots
§ dorsal ramus - shorter branch innervates back muscles & overlying skin
§ ventral ramus - longer branch innervates trunk/limbs muscles & forms nerve plexuses
§ ramus communicans - branches connecting ANS motor neurons w/ spinal nerve
§ meningeal branch - tiny spinal nerve branches reenters intervertebral foramen
§ innervates facet joints, intervertebral discs, meninges, blood vessels each cord segment
§ not found in thoracic region

25. Discuss the location and purpose of the rami communicantes.

ramus communicans - branches connecting ANS motor neurons w/ spinal nerve

26. Describe the general structure, function, and body locations of nerve plexuses. Explain how the nerve plexus arrangement protects a person from paralysis.

-              Nerve plexus - branching network of intersecting spinal nerves formed by ventral rami
§ fibers from several spinal nerves take different routes, primarily serves body limbs
§ each limb muscle is innervated by more than 1 spinal nerve
§ damage to a single spinal nerve still allows some limb function
§ seen in all body regions except for thoracic
§ cervical plexus
§ brachial plexus
§ lumbar plexus
§ sacral plexus
§ thoracic region (T2-T12) is served by ramus communicans

27. Define the term dermatome and discuss how it can be used in assessing spinal nerve damage.

-              Dermatomes - skin area (segment) innervated by cutaneous branches of a single spinal nerve
§ all spinal nerves except C1 contribute to a dermatome
§ important in assessing spinal nerve damage
§ up to 50% overlap can occur between adjacent dermatomes
§ destruction of a single spinal nerve does not result in complete numbness of affected body area
§ result of nerve plexus

28. Differentiate between PNS motor endings by effectors served and associated neurotransmitter(s).

-              PNS motor fibers activate its effector (target organ) via neurotransmitter release
1. skeletal muscle (voluntary) - stimulation occurs at a neuromuscular junction found in each muscle fiber
§ neurotransmitter = acetylcholine (ACh)
2. visceral muscle/glands* (involuntary) - stimulation occurs at knob-like varicosities associated w/ some smooth muscle cells
§ neurotransmitters = either ACh or norepinephrine

29. Define integration.

30. Define the terms reflex, reflex arc, spinal reflex, superficial reflex.

-              Reflexes - rapid, predictable, involuntary motor response
to a stimulus, some are protective in nature
§ helps maintain an upright position (e.g., prevent falls)
§ respond to/avoid painful stimuli
§ control autonomic visceral activities (e.g., peristalsis)
§ Classification:
§ target - either somatic or autonomic
§ type - either inborn or learned

-              Reflex arc - neural pathway from/to PNS through nerves with CNS controlling a reflex action

-              Spinal reflex - involuntary somatic reflex controlled by spinal cord but involves skeletal muscle movement

-              Superficial reflexes - are motor responses to stimulation (stroking) of overlying skin surface
§ they are graded simply as present or absent
§ involves both upper motor pathways & cord-level reflex arcs

31. Differentiate between an inborn (intrinsic) reflex and a learned (acquired) reflex.

type - either inborn(intrinsic) or learned(acquired)

32. Describe the purpose of reflex testing.

Reflex testing - indicates overall nervous system condition
§ assesses both sensory & motor functions
§ abnormal reflexes may indicate a nervous system problem before any other signs are apparent

33. Correctly order the components of a reflex arc.

-              1 receptor - located at stimulus action site

-              2 sensory neuron - transmits an afferent impulse towards a spinal cord integration center (horn interneurons)

-              3 integration center - spinal cord gray matter area where CNS interneurons interface with PNS sensory/motor neurons

-              4 motor neuron - conducts an efferent impulse away from an integration center to an effector

-              5 effector - target muscle or gland responding to an efferent impulse

34. List three elements dictating a reflex response.

35. List 2 types of information needed for coordinated muscle activity.

36. Differentiate between skeletal intrafusal and extrafusal muscle fibers.

37. Differentiate between muscle spindle afferent and efferent neurons.

38. Define the terms reciprocal inhibition, monosynaptic, polysynaptic, ipsilateral and contralateral.

reciprocal inhibition - agonist muscle contraction causes muscle relaxation of opposing muscle (antagonist)
§ mediated by muscle spindle

monosynaptic reflex - single synapse, no interneuron (direct) afferent ® efferent impulse transmission
§ axon carries a stimulatory (+) signal
2. polysynaptic reflex - multiple synapses, interneuron (indirect) afferent ® interneuron ® efferent impulse transmission
§ carries either a stimulatory (+); inhibitory (-) signal

ipsilateral - response occurs on same body side as stimulus
§ a finger prick on right hand causes withdrawal of right hand
2. contralateral - response involves opposite body side of stimulus occurring via interneurons in transverse gray commissure
§ stepping on broken glass w/ right foot causes right foot withdrawal but also a shifting of weight to left foot

39. Describe the possible effects of a monosynaptic and polysynaptic reflex.

1.        monosynaptic reflex - single synapse, no interneuron (direct) afferent ® efferent impulse transmission
§ axon carries a stimulatory (+) signal
2. polysynaptic reflex - multiple synapses, interneuron (indirect) afferent ® interneuron ® efferent impulse transmission
§ carries either a stimulatory (+) inhibitory (-) signal

40. List 2 ways to excite a muscle spindle.

41. Recall the action, synapse type, and body side controlled of each of the following reflexes:
-  Stretch/patellar reflex- Stretch reflex occurs when excessive stretch beyond normal causes the stretched muscle to contract

§ patellar reflex - tapping a patellar ligament stretches quadriceps muscle’s intrafusal muscle fibers exciting its muscle spindle

-  Golgi tendon reflex- Tendon reflex occurs when excessive tendon tension from muscle contraction causes contracting muscle to relax
§ Golgi tendon organ sensory input signals interneuron to inhibit (-) vigorously contacting muscle(s) before tendons tear

- Flexor reflex- Flexor reflex - withdrawal reflex initiated by a painful stimulus on one body side (finger prick® arm withdrawal)

- Crossed-extensor reflex- spinal cord integration center activates several interneurons on both sides of cord
§ effector on other body side performs opposite movement

Chapter 14
1. Describe the autonomic nervous system including, effectors served, type of control, response, and actions controlled.

-              Branch of PNS motor division controlling vital organs

-              Self-regulating(self-governing) system responsive to both short term/long term body needs

-              Mostly efferent motor neurons innervating viscera(ANS)

-              Actions support SNS

-              Raises or decreases heart/respiration rates, blood pressure, digestive process, and shunts blood to skeletal muscle, as is needed

2. Compare and contrast somatic nervous system and autonomic nervous system effectors (target organs), neural pathways, neurotransmitter types, and neurotransmitter effects on target organs.

1.        SNS motor neurons innervate somatic effectors (skeletal)

-              Single neuron pathway to its target organ

-              Sns motor neurons all release acetylcholine(Ach)

-              Effect is always stimulatory

2.        ANS motor neurons innervate visceral organs( smooth muscle cardiac muscle, and glands)

-              Two neuron pathway to its target organ

·      Preganglionic- 1^st neuron running from spinal cord to ANS ganglion

·       Preganglionic motor fibers all release ACh
§ Effect of ACh on postganglionic neuron/adrenal medulla is always stimulatory (+) (contracts/secretes)
- Parasympathetic fibers ® acetylcholine
- Sympathetic fibers ® acetylcholine

·      Postganglionic- 2^nd neuron running from ANS ganglion to target organ

-              ANS motor neurons release either ACh or norepinephrine /epinephrine (NE/EPI)

-              effect on target organ is either stimulatory (+) or inhibitory (-)

-              Postganglionic motor fibers release either ACh or NE/EPI
§ Effect of ACh or NE/EPI on target organ is either stimulatory (+) or inhibitory (-) (contracts/secretes) (relaxes)
- Parasympathetic fibers ® acetylcholine
- Sympathetic fibers ® norepinephrine/epinephrine

3. Compare and contrast the roles of the ANS parasympathetic and sympathetic divisions.

3.        Parasympathetic (basal)

 Keeps body energy usage low

 “D” activities - digestion, defecation, & diuresis (urine production)

 Actions are illustrated by a person who relaxes after a meal

1.  heart rate, blood pressure, & respiratory rates

2.  gastrointestinal tract activity

3. skin is warm, pupils are constricted

4.        Sympathetic (fight-flight-fright)

 Promotes increased blood flow to muscles while reducing it to organs

 “E” activities - exercise, excitement, emergency, & embarrassment (urine release)

 Actions are illustrated by a person who is threatened

1.  heart rate, blood pressure, & respiratory rates

2.  gastrointestinal tract activity

3. skin is cold/sweaty, pupils are dilated

4. Describe fiber origin, fiber length and ganglia in parasympathetic and sympathetic divisions.

5. Identify differences in target organ innervation by ANS parasympathetic and sympathetic divisions.

-  Parasympathetic Division (Rest & Digest)

• Origin: Craniosacral (brainstem and sacral spinal cord).

• Ganglia: Near or within target organs.

• Effects: Decreases heart rate, increases digestion, constricts pupils, stimulates glandular secretion.

- Sympathetic Division (Fight or Flight)

• Origin: Thoracolumbar (T1-L2 spinal segments).

• Ganglia: Sympathetic trunk ganglia and collateral ganglia near the spinal cord.

• Effects: Increases heart rate, dilates pupils, inhibits digestion, promotes sweat production.

6. Recall the general pathways of gray and white rami in relationship to the sympathetic trunk ganglia.

-  White Rami Communicantes

• Carry preganglionic sympathetic fibers from the spinal cord to the sympathetic trunk ganglia.

• Only found in spinal levels T1-L2 (where sympathetic fibers originate).

-  Gray Rami Communicantes

• Carry postganglionic sympathetic fibers from the sympathetic trunk back to spinal nerves for distribution to target organs.

• Found at all spinal levels for widespread innervation.

7. Describe sympathetic trunks and sympathetic trunk ganglia.

-               Sympathetic Trunks

• Paired chains of ganglia running along each side of the vertebral column from the base of the skull to the coccyx.

• Serve as a pathway for sympathetic nerves to ascend or descend before synapsing.

-                Sympathetic Trunk Ganglia

• Collections of sympathetic neuron cell bodies along the sympathetic trunk.

• Examples include cervical, thoracic, lumbar, and sacral ganglia.

• Provide sympathetic innervation to various target organs (e.g., heart, lungs, digestive tract).

8. Recall location of sympathetic chain ganglia pairs (e.g., 4 lumbar).

-              3 cervical

-              11 thoracic

-              4 lumbar

-              1 sacral

-              1 coccygeal

9. Describe the function of visceral sensory neurons.

-              Visceral sensory neurons - first link in autonomic reflexes

-              sends chemical changes (pH), stretch, irritation information from deep viscera to spinal cord

-              cell bodies are in either dorsal root ganglia or cranial nerve Ganglia

10. Correctly order the elements of visceral reflex arc.

Stimulus

1-       receptor in viscera

2-       visceral sensory neuron

3-       integration center

-              may be preganglionic neuron (as shown)

-              may be a dorsal horn interneuron

-              may be within walls of gastrointestinal tract

4-       motor neuron (two neuron chain)

-              pre and postganglionic neuron

5-       visceral effector

response

11. List 2 major ANS neurotransmitters.

- acetylcholine and norepinephrine

12. Differentiate between cholinergic and adrenergic fibers.

1. cholinergic fibers all release ACh

- sympathetic preganglionic axons

- parasympathetic preganglionic/postganglionic axons

2. adrenergic fibers release either norepinephrine (NE) or EPI

- sympathetic postganglionic axons

13. Differentiate between cholinergic and adrenergic receptors.

1. cholinergic receptors all bind ACh

- two subclasses = nicotinic, muscarinic

- nicotinic receptors bind ACh, always stimulatory

regardless of subclass (N1, N2)

6-       SNS skeletal muscle (N1), ANS postganglionic neurons (N2), adrenal medulla cells

7-       muscarinic receptors bind ACh, stimulatory or inhibitory depending on subclass (M1, M2, M3, M4, M5)

8-       parasympathetic controlled target organs (cardiac muscle, smooth muscle, glands), few sympathetic targets

9-       muscarinic receptor location determines ACh effect

2. adrenergic receptors bind NE or epinephrine

- two subclasses = α, b

- alpha receptors - bind NE/EPI, either stimulatory or inhibitory depending on receptor subclass (1 ,2)

• sympathetic controlled smooth muscle, heart muscle, adrenal/prostate glands

10- beta receptors - bind NE/EPI, either stimulatory or inhibitory depending on receptor subclass (b1 , b2 , b3)

• sympathetic controlled smooth muscle in blood vessel/ digestive system walls, heart muscle, pancreas

14. Describe neurotransmitter effects on 2 types of cholinergic receptors.

-              Nicotinic Receptors (N)

·      Location: Found in autonomic ganglia, adrenal medulla, and neuromuscular junctions.

·      Effect: Activation leads to excitation (e.g., muscle contraction at the neuromuscular junction) by opening ligand-gated ion channels, allowing Na⁺ and K⁺ ion flow,

-              Muscarinic Receptors (M)

·      Location: Found in the heart, smooth muscle, and glands.

·      Effect: Can be excitatory or inhibitory depending on the subtype:

·      M1, M3, M5: Excitatory effects (e.g., smooth muscle contraction, gland secretion).

·      M2, M4: Inhibitory effects (e.g., decreased heart rate via inhibition of adenylate cyclase).

15. Describe neurotransmitter effects on 2 types of adrenergic receptors.

-              Alpha (α) Receptors

·      α1: Located in blood vessels and smooth muscle. Causes vasoconstriction and increased blood pressure by activating phospholipase C (↑ intracellular Ca²⁺).

·      α2: Found in presynaptic neurons. Inhibits neurotransmitter release by decreasing cAMP levels.

-              Beta (β) Receptors

·      β1: Located in the heart. Increases heart rate and contractility by stimulating adenylate cyclase (↑ cAMP).

·      β2: Found in bronchial and vascular smooth muscle. Causes bronchodilation and vasodilation by relaxing smooth muscle (↑ cAMP).

16. Explain ANS effects of atropine, epinephrine, pseudoephedrine, alpha-blockers and beta-blockers.

§ Atropine - blocks parasympathetic effects (anticholinergic), binds to muscarinic receptor inhibiting ACh binding, which ­ heart rate
§ Epinephrine (EpiPen®) - relaxes bronchiole smooth muscle by binding to its b2 receptors, rapidly reverses severe allergic reaction by opening up airways + ­ BP
§ Pseudoephedrine (Sudafed®) - ephedrine containing sympathomimetic, stimulates a-adrenergic receptors of nasal blood vessels to contract = less fluid leakage
§ Alpha-blocker (Minipress®) - binds to a receptors inhibiting NE-induced vasoconstriction, treats hypertension (­BP)
§ Beta-blocker (Lopressor®) - binds to heart b1 receptors to ¯ heart rate/prevent arrhythmias w/o affecting sympathetic activity
§ “blocks” stimulatory effect of NE binding to heart b1 receptors

17. Define the term dual innervation.

Dual innervation - most visceral organs are innervated by both sympathetic/parasympathetic fibers

18. Describe the dynamic antagonism exhibited by parasympathetic and sympathetic divisions.

Dynamic antagonism - both divisions are partially active, which provides precise control of visceral(deep) activity

19. List unique sympathetic division functions.

§ Regulates several functions not subject to parasympathetic influence
§ adrenal medulla activity, sweat glands, arrector pili muscles, kidneys, most blood vessels (e.g. heart coronary artery)
§ Controls:
§ thermoregulatory responses to heat - ­ skin blood vessel dilation (flush) activates sweat glands to cool body
§ kidney renin release - ­ blood pressure
§ metabolic effects - ­ metabolic rate, blood glucose level, mental alertness, fat mobilization
§ cannot be reversed by parasympathetic division

20. Contrast activation effects of parasympathetic and sympathetic divisions.

- Active opposition demonstrated by both systems to each other is more like one of complementary effects

1. parasympathetic division - ACh release exerts a short-lived, highly localized control over its effectors

- ACh is quickly destroyed by acetylcholinesterase in synapse

2. sympathetic division - NE/EPI release exerts a long-lasting, widespread (diffuse) control over its effectors

- NE is inactivated more slowly than ACh

- EPI remains in blood until destroyed by liver

- adrenal gland also releases more NE/EPI

21. Explain how the hypothalamus controls ANS activity.

Hypothalamus - main integration center of ANS activity

11- limbic system subconsciously influences hypothalamic function

12- cerebral cortex, reticular formation, spinal cord all provide additional controls

Hypothalamic control:

13- heart activity, blood pressure (↑ by EPI/NE release)

14- body temp, water balance, endocrine activity

15- regulates emotional stages (rage, pleasure) biological drives (hunger, thirst, sex)

16- reactions to fear including “fight-flight-or-fright” system

Sample Multiple-Choice Questions (* = correct answer)
1. What is the gray matter-white matter pattern of cerebral cortex starting from outside and moving inctowards the central canal?
a. gray-white-gray *
b. gray-white
c. white-gray
d. white-gray-white

2. Association fibers serve to connect:
a. one cerebellar hemisphere to the other
b. different parts of same cerebral hemisphere *
c. cerebral cortex with spinal cord
d. one cerebral hemisphere to the other

3. Which of the following is a shallow groove separating adjacent gyri (ridges)?
a. sulcus *
b. fissure
c. hemisphere
d. furrow

4. The filium terminale:
a. anchors the spinal cord to coccyx *
b. is found at the inferior end of spinal cord
c. attaches the spinal cord to its vertebral body
d. is associated with the cauda equina

5. The thin, delicate connective tissue layer directly inferior to the arachnoid space is called:
a. dura mater
b. subarachnoid
c. arachnoid
d. pia mater *

6. Which of the following are internal sensory receptors monitoring changes in skeletal muscle spindle
length?
a. golgi tendon organs
b. intrafusal muscle fibers *
c. efferent motor fibers
d. extrafusal muscle fibers

7. What coarse connective tissue covers groups of nerve fibers known as fascicles?
a. endoneurium
b. epineurium
c. perineurium *
d. paraneurium

8. Vibration, touch, and pressure stimuli are all detected by:
a. nociceptors
b. photoreceptors
c. mechanoreceptors *
d. chemoreceptors

9. The stretch reflex is also called a _______ reflex.
a. golgi tendon organ
b. patellar *
c. cross-extensor
d. flexor

10. The spinal nerve ventral root contains ________ __________ fibers:
a. somatic afferent
b. visceral sensory
c. visceral efferent *
d. somatic sensory

11. Sympathetic fibers leave spinal cord in the ___________ regions whose postganglionic fibers secrete
_______________.
a. craniosacral / norepinephrine
b. thoracolumbar / acetylcholine
c. craniosacral regions / acetylcholine
d. thoracolumbar / norepinephrine *

12. Which of these effectors (target organs) is directly controlled by the somatic nervous system?
a. smooth muscle
b. cardiac muscle
c. skeletal muscle *
d. most glands

13. What effect would acetylcholine have when binding to a cholinergic muscarinic receptor?
a. no response
b. stimulation
c. inhibition
d. either stimulation or inhibition *

14. Which of the following is true about the autonomic nervous system (ANS)?
a. branch of PNS sensory division
b. controls actions of body limbs
c. involuntary motor control *
d. mostly somatic afferent neurons

15. What effector is innervated (supplied) by sympathetic neurons but not by parasympathetic neurons?
a. salivary gland
b. sweat gland *
c. pancreas
d. cardiac muscle