Unit 3 Exam Study Guide

What are the structural divisions of the nervous system?

Central and Peripheral nervous system

What are the components of the central nervous system?

• Consists of the  brain and spinal cord

• Involved in processing and coordinating signals

• Brain is involved higher level functions, including:

• Intelligence

• Memory

• Learning

• Emotion

What are the components of the peripheral nervous system?

• Consists of nerves leading to/from the brain and spinal cord

What are the subdivisions of the PNS? What is the function of each division?

• Sensory division AKA “afferent division” 

• Provides sensory information to the  Central Nervous System

• Motor division

• AKA efferent

• Carries motor commands from the central nervous system to the peripheral tissues

What are the types of nervous tissue?

1. Neuron/ Nerve cells/ Nerve fibers

2. Neuroglia

What is the function of a neuron?

• Neurons are the excitable cells that carry impulses

• Responsible for the transmission of signals/information within the nervous system

What is the function of neuroglia?

• AKA glial cells

• Non-excitable cells found within the nervous system

• Involved in the support, Protection, maintenance, and isolation of neurons

What are the characteristics of neurons?

• Have a high metabolic rate

• Extreme longevity

• Non-mitotic: Do not divide

In a written question be able to draw a basic neuron. Label all parts of the neuron and state their functions

1. Dendrite: Receives information from a neuron and send information to the cell body

2. Cell body: Receives information from the dendrite and sends information to the axon

3. Axon: Receives information from the cell body and send information to the axon button

4. Myelin: Insulation

5. Axon Button: Synapse and release neurotransmitters

What are cell bodies called in the CNS? PNS?

Central nervous system: Nuclei

Peripheral nervous system: Ganglia

What are the types of cell junctions? Where is each junction located?

• Synapse: Between axon and dendrite of two neurons

• Neuromuscular junction: Between axon and muscle

• Neuroglandular junction: Between axon and gland

In a written question What are the structural classifications of neurons? For each neuron, describe its appearance and state its function.

• Structural classification of neurons are based on the number of processes the neurons contains

• Multipolar

• Contain

• multiple short dendrites

• Single, long axon

• Typically motor in function

• Bipolar

• Contain

• single dendrite

• long single axon

• Found only in the following specialized sensory organs

• Ear, nose, eye

• Unipolar

• Contain one process that splits near the cell body

• Contains both the dendrite and the axon

• Usually sensory in function

In a written question What are the functional classifications of neurons? For each neuron, describe its appearance and state its function.

• Functional classifications of neurons are based off of the direction of nerve impulses in relation to the Central nervous system

• Sensory (afferent) neurons

• Carry impulses towards the CNS from sensory receptors in the organs

• Most are unipolar neurons

• Motor (efferent) neurons

• Carry impulses away from the brain/CNS towards effectors

• Effectors = muscles/glands

• Most are multipolar neurons

• Interneurons

• AKA association or internuncial neurons

• Carries information between sensory and motor neurons

• Found within the CNS

• Most are multipolar neurons

In a written question, What are the types of neuroglia in the CNS? For each neuron, state its function.

Astrocytes

• Functions

• Maintain the blood brain barrier

• Support neurons and link them to capillaries (blood supply)

• Recapture and recycle released neurotransmitters

Oligodendrocytes

• Produce myelin in CNS

Microglia

• Engulf invading microorganisms and injured/dead neurons

What is the function of the Schwann cell in the PNS.

• Wrap around peripheral nervous system neurons

• Support and insulate the axon

• Produce myelin

What is myelin? What is its histology? What is its function?

• Lipid-protein complex that surrounds the axon

• Improves the speed of nerve impulses

• Forms the Nodes of Ranvier

Histology: Adipose Connective Tissue

What are meninges?

• Protective membranes the cover the brain and spinal cord

In a written question What are the layers of the meninges from superficial to deep? What is the histology of each

Layer?

Dura mater: dense irregular connective tissue

Arachnoid Mater: Simple squamous epithelium and elastic connective tissue

Pia Mater: Areolar connective tissue

What is the function of the dural venous sinuses?

• Blood channels that drain deoxygenated blood from the brain, carrying blood back toward the heart

• Ex. The superior sagittal sinus and transverse sinus

What are arachnoid villi?

• Projections of the arachnoid into the dural sinuses (including the superior sagittal sinus)

• Allows for CSF to pass from the subarachnoid space into the bloodstream to be reabsorbed

What are the ventricles in the brain? What are their functions?

Lateral ventricles (pair): empty CSF into the interventricular foramen, creation of CSF

Third Ventricle: drains CSF into the cerebral aqueduct

Fourth Ventricle: drains CSF into the median and lateral apertures

In a written question using a flow chart, state the pathway of CSF flow through the brain.

1. Lateral ventricle

2. Interventricular foramen

3. Third ventricle

4. Cerebral aqueduct

5. Fourth ventricle

6. Medial and lateral apertures

7. Subarachnoid space

8. Arachnoid villi

9. Dural Venous Sinus

What is the function of the choroid plexus? Where are they found?

Makes Cerebrospinal fluid

Within the ventricles of the brain

What is the composition of CSF?

Similar to blood plasma but with less protein

Glucose, Na+, Cl-

What are the functions of CSF?

Shock absorption

Internal support

Transports nutrients and waste

What are the regions of the brain? Know both common and scientific names.

• Forebrain (prosencephalon)

• Cerebrum

• Thalamus

• Hypothalamus

• Midbrain (mesencephalon)

• Cerebral peduncles

• Corpora quadrigemina

• Hindbrain (rhombencephalon)

• Cerebellum

• Pons

• Medulla Oblongata

What separates the lobes of the cerebrum? What connects them?

Separated by: longitudinal fissure

Connected by: corpus callousm

What is the function of gyri and sulci?

Increase the surface area of the brain

In a written question what are the lobes of the cerebrum? What is the general function of each lobe?

Frontal: Abstract thought, mood

Insula: Taste, pain

Parietal: Taste, sensory integration

Occipital: vision

Temporal: Hearing, Smell

What are the sulci of the cerebrum? What lobes of the cerebrum does each divide?

• Lateral sulcus: between the temporal and parietal lobes

• Central sulcus: between the frontal and parietal lobes

• Parieto-occipital sulcus: between parietal and occipital lobes

Why is gray matter of the brain gray? Why is white matter white?

gray matter: non-myelinated

White matter: myelinated

What are tracts?

Axon bundles traveling to similar destination

In a written question what are the types of tracts? What does each tract connect?

Association Tracts

• Connect regions within the same hemisphere

Commissural Tracts

• Connections between the right and left hemispheres

• Ex. Corpus Collosum

Projection Tracts

• Connects cerebrum to “lower”  brain areas and the spinal cord

What is the function of ascending association tracts? Descending tracts?

• Ascending: carry sensory information towards the cerebrum

• Descending: carry motor information away from the cerebrum

What is the function of the pre-central gyrus?

• Pre-central Gyrus

• Primary motor Area

• Motor nerve tracts originate here

What is the function of the Brocha’s area of the brain?

• Speech Area

• Broca’s Area (left hemisphere only)

• Controls muscles necessary for vocalization

What is the function of the post-central gyrus?

• Post-central Gyrus

• Primary sensory Area

• Termination of pathways that carry perception for pain, touch, pressure, and temperature

What is the function of the thalamus?

Relay station for sensory and motor information

What are the functions of the hypothalamus?

• Gray matter that forms the floor of the 3rd ventricle

• Functions:

• Regulates behavior associated with emotions

• Controls most of the autonomic nervous system

• Regulates thermoregulation, appetite, and thirst

• Controls pituitary gland secretion

What are the components of the mesencephalon?

• Cerebral Peduncles

• Corpora Quadrigemina

What are the functions of the cerebral peduncles?

• Motor projection tracts

• Descending fibers from the cerebral cortex to the spinal cord

• Sensory tracts

• Ascending tracts from the spinal cord to the thalamus

In a written question, What are the components of the corpora quadrigemina? What is the function of each?

• Superior colliculi of the corpora quadrigemina: Responsible for involuntary eye/head movement in response to Visual stimuli

• Inferior colliculi of the corpora quadrigemina: Responsible for involuntary eye/head movement in response to Auditory stimuli

What are the components of the rhombencephalon?

Pons, cerebellum, medulla oblongata

What is the function of the pons?

Relay station for sensory and motor tracks

What is the function of the cerebellum?

Motor coordination

What are the components of the medulla oblongata? What is the function of each Component?

• Vital Centers

• Regulate respiratory rate, heart rate, and vasomotor control (blood pressure)

• Non-Vital Centers

• Regulate coughing, swallowing, and vomiting

What are the functions of the spinal cord?

• Functions of the spinal cord and associated spinal nerves

1. Conduct

sensory/motor impulses to/from the brain via spinal tracts

2. Reflexes

Where is gray matter located in the spinal cord? White matter?

White matter: outermost

Grey matter: innermost

Why is gray matter gray? Why is white matter white?

Gray matter: not myelinated

White matter: myelinated

What is the function of the ascending tracts?

• sensory pathways that carry information toward the brain

• Cross over at medulla or point of entry

What is the function of the descending tracts?

• motor pathways from the cerebral cortex or cerebellum

• Cross over at or above the medulla

What is found within the central canal?

Filled with Cerebrospinal fluid

What is paralysis? What causes it?

• Complete or partial loss of motor function

• Caused by localized damage to the spinal cord

What is meningitis? What causes it?

• inflammation of the meninges

• Caused by bacterial(more dangerous)  or viral infection(less dangerous)

What is encephalitis? What causes it?

• Inflammation of the brain

• Can be caused by bacterial or viral infections

• In rare cases it can be caused by autoimmune conditions

What is multiple sclerosis? What causes it?

• autoimmune condition that results in the deterioration of myelin sheaths

• Results in slowed nerve impulses and “miscommunication” between neurons

What is a stroke? What is an ischemic stroke? Hemorrhagic stroke?

• Blood flow within the brain is 

• Brain tissue in the area dies due to lack of oxygen

• Can be caused by blood clot or arthrosclerosis

Ischemic: blood clot 

Hemorrhagic: bleeding