Exam 3 by rykb1003

Cranial Nerve I

olfactory; sensory (smell) function

Cranial Nerve II

optic; sensory (vision) function

Cranial Nerve III

oculomotor; motor function

Cranial Nerve IV

trochlear; motor function

Cranial Nerve V

trigeminal; both sensory (general sensation) and motor function

Cranial Nerve VI

abducens; motor function

Cranial Nerve VII

facial; both sensory (taste) and motor function

Cranial Nerve VIII

vestibulocochlear; sensory function (hearing and balance) and some motor function

Cranial Nerve IX

glossopharyngeal; both sensory (taste) and motor function

Cranial Nerve X

vagus; both sensory (taste) and motor function

Cranial Nerve XI

accessory; motor function

Cranial Nerve XII

hypoglossal; motor function

Peripheral Nervous System (PNS)

includes all neural structures outside the brain and spinal cord

- sensory receptors, afferent and efferent nerves, ganglia, motor endings

communication lines between the CNS and the rest of the body

Sensory (Afferent) Division

somatic and visceral sensory nerve fibers; conducts impulses from receptors to the CNS

Motor (Efferent) Division

motor nerve fibers; conducts impulses from the CNS to effectors (muscles and glands)

Somatic Nervous System

somatic (voluntary) motor nerve fibers; conducts impulses from the CNS to skeletal muscles

Autonomic Nervous System (ANS)

visceral (involutary) motor nerve fibers; conducts impulses from the CNS to cardiac muscle, smooth muscle, and glands

Sympathetic Division

mobilizes body systems during activity

- fight or flight

Parasympathetic Division

conserves energy; promotes "house-keeping" functions during rest

CNS vs PNS

Central Nervous System

- brain and spinal cord

- integration and control center (interprets sensory input and dictates motor output

Peripheral Nervous System

- nervous system outside CNS, mainly spinal nerves and cranial nerves

- communication lines between CNS and the rest of the body

Group A Fibers

- largest diameter

- myelinated somatic sensory and motor fibers of skin, skeletal muscles, and joints

- transmit at 150 m/s

Group B Fibers

- intermediate diameter

- lightly myelinated fibers

- transmit at 15 m/s

Group C Fibers

- smallest diameter

- unmyelinated

- transmit at 1 m/s

Astrocytes

CNS glial cells; most abundant

- support and brace neurons and anchor them to nutrient supply lines

- play a role in making exchanges between capillaries and neurons

- guide migration of young neurons and formation of synapses

- control chemical environment

Oligodendrocytes

CNS glial cells; fewer processes than astrocytes

- line up along thicker nerve fibers and wrap their processes tightly around the fibers, producing a myelin sheath

Satellite Cells

PNS neuroglia; surround neuron cell bodies with similar function to astrocytes

Schwann Cells (Neurolemmocytes)

PNS neuroglia; surround all nerve fibers and form myelin sheaths around thicker nerve fibers; function similarly to oligodendrocytes

- vital to regeneration of damaged peripheral nerve fibers

Action Potentials

principal wayneurons send signals (long distance communication)

- only occurs in muscle cells and axons of neurons

- also referred to as nerve impulses

Action Potential: Resting State

all gated Na+ and K+ channels are closed

Action Potential: Depolarization

Na+ channels open

- depolarizing local currents open voltage gated channels and Na+ rushes in causing more depolarization

Action Potential: Repolarization

Na+ channels are inactivating and K+ channels open

- membrane permeability to Na+ declines to resting state

(repolarization is when the membrane returns to resting membrane potential)

Action Potential: Hyperpolarization

some K+ channels remain open and Na+ channels reset

- allows excessive K+ efflux (inside of membrane becomes more ngative than in resting state)

Cerebral Hemispheres

form the superior part if the brain; accounts for 83% of the brain

Cerebral Cortex

conscious mind

- enables us to be aware of ourselves and our sensations, to communicate, remember, understand, and initiate voluntary movement

Cortical Gray Matter

- localizes and interprets sensory inputs

- controls voluntary and skilled skeletal muscle activity

- functions in intellectual and emotional processing

Basal Nuclei (Ganglia)

- subcortical motor centers

- help control skeletal muscle movements

Diencephalon

- forms the central core of the forebrain, surrounded by cerebral hemispheres

- includes thalamus, hypothalamus, and epithalamus

Thalamus

- relays sensory impulses to cerebral cortex for interpretation

- relays impulses between cerebral motor cortex and lower motor centers

- involved in memory processing

Hypothalamus

- chief integration center of ANS

- regulates body temperature, food intake, water balance, thirst, and biological rhythms and drives

- regulates hormonal output if anterior pituitary gland

- acts as an endocrine organ, producing posterior pituitary hormones ADH and oxytocin

Epithalamus

- forms the roof of the third ventricle

- extending from its posterior border is the pineal gland (secretes melatonin, helping regulate the sleep wake cycle)

Limbic System

- includes cerebral and diencephalon structures

- mediates emotional response

- involved in memory processing

Brain Stem

- consists of the midbrain, pons, and medulla oblongata

Midbrain

- contains visual and auditory reflex centers

- contains subcortical motor centers

- contains nuclei for cranial nerves III and IV

- contains projection fibers

Pons

- relays information from the cerebrum to the cerebellum

- cooperates with the medullary respiratory centers to control respiratory rate and depth

- contains nuclei of cranial nerves V-VII

- contains projection fibers

Medulla Oblongata

- relays ascending sensory pathway impulses from skin and proprioceptors through nuclei cuteatus and gracilis

- contains visceral nuclei controlling heart rate, blood vessel diameter, respiratory rate, vomiting, coughing, etc

- contains nucei of cranial nerves VIII-X and XII

- contains projection fibers

- site of decussation of pyramids

Reticular Formation

- maintains cerebral cortical alertness

- filters out repetitive stimuli

- helps regulate skeletal and visceral muscle activity

Cerebellum

- processes information from cerebral motor cortex, proprioceptors, and visual and equilibrium pathways

- provides "instructions" to cerebral motor cortex and subcortical motor centers, resulting in smooth, coordinated skeletal muscle movements

- responsible for balance and posture