A&P 2, Exam #1 (Siegfried, SBU)

Chapters 12-14

divisions of nervous tissue (2)

1. central nervous system
2. peripheral nervous system

central nervous system components (2)

1. brain
2. spinal cord

peripheral nervous system components (4)

1. nerves
2. ganglia
3. enteric plexuses
4. sensory receptors

what does the central nervous system do?

processes sensory information and creates thoughts, emotions, and memories

what are nerves?

bundles of axons

what are ganglia?

small masses of nervous tissue

what are enteric plexuses?

neurons in organs of GI tract that help regulate the digestive system

what are the sensory functions of the nervous system?

sensory receptors detect internal and external stimuli and carry information to the brain and spinal cord

what are the integrative functions of the nervous system?

processing of sensory information and determining response

what are the motor functions of the nervous system?

responding to information

what are neurons?

nerve cells that form networks of the brain and aid in sensing, remembering, controlling, and glandular secretions

what are neuroglia?

connective tissue cells in nervous system cells that support, protect, and nourish.

what is electrical excitability?

a neurons ability to respond to a stimulus and convert it into to an action potential

what are the 3 main parts of a neuron?

1. cell body
2. dendrites
3. axon

what are the 3 structural classifications of neurons?

1. multipolar
2. bipolar
3. unipolar

what are the 3 functional classifications of neurons?

1. sensory
2. motor
3. interneurons

multipolar neuron classifications

several dendrites, one axon, found in brain and spinal cord

bipolar neuron classifications

one main dendrite, one axon, found in retina, inner ear, and olfactory area of the brain

unipolar neuron classifications

one process comes off of the neuron cell body, found in sensory receptors such as touch, pressure, pain, and heat

what are sensory receptors?

a structure of the nervous system that monitors changes in the external or internal environment

3 divisions of the PNS

1. somatic nervous system 2. automatic nervous system 3. enteric nervous system

2 branches of the ANS

1. sympathetic division 2. parasympathetic division

sensory/afferent neuron function

carry information to the CNS

motor/efferent neuron function

carry information away from CNS

interneurons function

conduct from sensory to motor, located in CNS

neuroglia sites

4 in CNS, 2 in PNS

what are astrocytes?

large star-shaped neuroglia in the CNS that support neurons, create a blood-brain barrier, and maintain nerve impulse generation

what are oligodendrocytes?

neuroglia that produce and maintain the myelin sheath around nerve cords

what is a dendrite?

the receiving or input portion of a neuron

what are microglia?

small cells that move about in inflamed brain tissue and are phagocytic

what type of astrocytes are found in grey matter?

protoplasmic astrocytes

what type of astrocytes are found in white matter?

fibrous astrocytes

what are ependymal cells?

a single layer of epithelial cells with cilia and microvilli that line the ventricles of the brain and central canal that form cerebrospinal fluid and assist in circulation

what are satellite cells?

cells that regulate the exchange of materials between neuronal cell bodies and interstitial fluid

what are schwann cells?

cells that produce a myelin sheath around PNS neurons

what is the myelin sheath?

lipid and protein covering of some axons

what is grey matter composed of?

myelinated fibers

what is white matter composed of?

neuron cell bodies and unmyelinated fibers

what are the 4 types of ion channels?

1. leak channels
2. ligand-gated channels
3. mechanically-gated channels
4. voltage-gated channels

what are leak channels?

channels with K+ and Na+ that randomly alternate between open and closed

what are ligand-gated channels?

channels that open and close in response to ligand channels

what are mechanically-gated channels?

channels that respond to mechanical vibrations

what are voltage-gated channels?

channels that respond to a change in membrane potential

what is an action potential?

a rapid sequence of events that reverses the membrane potential and restores to resting state

what are Nissl bodies?

clusters of rough ER

what is the spinal cord protected by?

vertebrae, meninges, and cerebrospinal fluid

what are the 3 layers of the meninges?

1. dura mater
2. arachnoid mater
3. pia mater

how many pairs of cervical nerves are there?

8

how many pairs of thoracic nerves are there?

12

how many pairs of lumbar nerves are there?

5

how many pairs of coccygeal nerves are there?

1

length of adult spinal cord

42-45 cm

cervical enlargement/plexus:

C4-T1

lumbar enlargement/plexus:

T9-T12

conus medullaris:

L1-L2

how many pairs of spinal nerves are there?

31

how many pairs of cranial nerves?

12

brachial plexus:

C5-C8+T1

sacral plexus:

L4-L5+S1-S4

coccygeal plexus:

S4-S5

function of the cervical plexus

supplies the skin and muscles of the head, neck, superior portion of the shoulders and chest, and diaphragm

function of brachial plexus

provides almost entire nerve supply to the shoulders and upper limbs

what are the 6 nerves of the lumbar plexus?

1. iliohypogastric
2. ilioinguinal
3. genitofemoral
4. lateral femoral cutaneous
5. femoral
6. obturator

what is the function of the blood brain barrier?

to protect brain cells from harmful substances and pathogens

what is the function of cerebrospinal fluid?

to protect the brain and spinal cord against chemical and physical injuries and carry oxygen, glucose, and other substances to nervous tissue cells

what is the function of pyramids?

to control voluntary movements of the limbs and trunk

what is the function of the pons?

relays nerve impulses related to voluntary skeletal muscle movements from the cerebrum to the cerebellum

what is the function of the midbrain?

conveys motor impulses from the cerebrum to the cerebellum and spinal cord, sends sensory impulses from impulses from the spinal to the thalamus, and regulates auditory and visual reflexes

what is the function of the reticular formation?

helps regulate muscle tone, alerts the cortex to incoming sensory signals, and is responsible for maintaining consciousness and awakening from sleep

what is the function of the thalamus?

conscious recognition of pain, temperature, light, and touch, and knowledge cognition

what are the functions of the hypothalamus?

control of the ANS, production of hormones, regulation of emotional and behavioral patterns, regulation of eating and drinking, control of body temperature, regulation of circadium rhythm and consciousness.

what does the pineal gland secrete?

melatonin

what is the cerebrum?

the seat of intelligence

what are association tracts?

tracts that conduct nerve impulses between gyri in the same hemisphere

what are commissural tracts?

tracts that conduct nerve impulses from gyri in one cerebral hemisphere to corresponding gyri in another cerebral hemisphere.

what are projection tracts?

tracts that conduct nerve impulses from the cerebrum to lower parts of the CNS

what are the functions of basal nuclei?

regulation of initiation and termination of movements, controls subconscious contractions, and initiates and terminates cognitive processes

what is the limbic system?

the emotional brain (deals with pain, pleasure, affection, anger…)

alpha waves

awake and resting with eyes closed

beta waves

sensory input and and mental activity

theta waves

emotional stress or disorder

delta waves

deep sleep in adults, awake in infants

12 cranial nerves

1. olfactory
2. optic
3. oculomotor
4. trochlear
5. trigeminal
6. abducens
7. facial
8. vestibulocochlear
9. glossopharyngeal
10. vagus
11. accessory
12. hypoglossal

function of cranial nerves pneumonic

1. some
2. say
3. marry
4. money
5. but
6. my
7. brother
8. says
9. big
10. brains
11. matter
12. more

cranial nerves pneumonic

1. original
2. oblong
3. oracles
4. try
5. to
6. anger
7. fierce
8. vanquishing
9. gorillas
10. via
11. army
12. harpoons

olfactory (1) nerve

special sensory for smell

optic (2) nerve

special sensory for vision

oculomotor (3) nerve

controls muscles that move the eyeballs

trochlear (4) nerve

movement of eyeballs on superior oblique

trigeminal (5) nerve

biggest nerve. touch, pain, and thermal sensations from face, chewing

abducens (6) nerve

movement of eyeballs

facial (7) nerve

taste from anterior tongue, touch, pain, and thermal sensations from inner ear, control of facial expressions, secretion of tears and saliva

vestibulocochlear (8) nerve

sensory for equilibrium and hearing

glossopharyngeal (9) nerve

taste, swallowing, saliva

vagus (10) nerve

swallowing, vocalization, coughing

accessory (11) nerve

movement of head and pectoral girdle

hypoglossal (12) nerve)

speech, manipulation of food, swallowing

graded potentials

short-distance communication only

action potentials

allow communication over long distances within the body

resting membrane potential arises from three major factors, what are they?

1. unequal distribution of ions in the ECF and cytosol
2. inability of most anions to leave the cell
3. electrogenic nature of the Na+-K+ ATPases