CNS (4)

Question 1

parts of the CNS

Answer 1

brain and spinal cord

• aka is a collection of neurons that forms specialized signaling networks

brain: encased by the bones of the cranium
spinal cord: runs through the bones of the vertebral column

Question 2

meninges (def, function + parts)

Answer 2

= tissue membranes that lie between bones and the soft tissues of the CNS

stabilizes and protects neural tissue

• dura matter
• arachnoid membrane
  - subarachnoid space contains cerebrospinal fluid
• pia mater

Question 3

ventricles of the brain: def

Answer 3

a communicating network of cavities
- lateral ventricles = 1st and 2nd ventricles
- through brain stem and into spinal cord via central canal = 3rd and 4th ventricles

Question 4

ventricles of the brain: functions

Answer 4

produces CSF

physical protection… PROTECT
- keeps brain tissue buoyant to reduce pressure and protect from mechanical insult
- absorbs shock

chemical protection… CLEAN UP
- BBB
- delivers nutrients to the brain and removes waste
- allows for a tightly regulated extracellular environment

Question 5

where is CSF produced, and what is this areas function?

Answer 5

in the choroid plexus of the ventricles

• capillaries and ependymal cells meet here
• plasma gets filtered into ventricles

therefor the choroid plexus has ependymal cells selectively transport solutes, and water follows by osmosis

Question 6

CSF and plasma

Answer 6

similar chemical composition but CSF has very low protein content

Question 7

how is CSF reabsorbed to blood, from the subarachnoid space

Answer 7

via the arachnoid villi that project into the venous space
- nutrients from CSF play a big role here in blood!

Question 8

CSF adult volume and turnover rate

Answer 8

150mL in adult ventricles
turns over 3-4x/day
rate of secretion and absorption is equal

Question 9

BBB

Answer 9

has tight junctions and astrocyte foot processes
- acts as a border control

Question 10

BBB and tight junctions + ex

Answer 10

brain capillaries have tight junctions that prevent movement of larger solutes between endothelial cells

ex: limits movement of hydrophilic substances that would pass easily via the paracellular pathway of exchange epithelium

**these capillaries can be super leaky in nephron

Question 11

BBB and astrocyte foot processes

Answer 11

secrete paracrines onto endothelial cells that
promote tight junction formation

• also responsible for upregulating and maintaining the structure of tight junctions
• are essentially little pads covering up the capillaries

Question 12

BBB and lymph system

Answer 12

takes care of any leaky capillaries in the BBB

Question 13

metabolic needs of O2 in neural tissue

Answer 13

passes via diffusion freely across BBB
brain gets 15% of blood pumped by heart at rest

**this % is a constant amount that is determined by need

Question 14

metabolic needs of glucose in neural tissue

Answer 14

brain is responsible for about 20% of body
total glucose consumption
- important because progressive hypoglycemia leads to confusion which lead to unconsciousness and then death

Question 15

how does glucose cross the BBB

Answer 15

via ependymal cells w apical or basolateral transporter

Question 16

what cannot the brain do with glycogen/FA metabolism

Answer 16

use it when glucose is low
- cardiac and skeletal muscles can do this

Question 17

gray matter

Answer 17

made up of nucleus (clusters of cell bodies) and dendrites, synapses, axon termini

brain: superficial and then deep inside too

spine: inside
divided into dorsal (sensory,afferent) and ventral (motor,efferent) horns
- pseudounipolar sensory neurons also present
- cell bodies live in dorsal root ganglion

Question 18

white matter

Answer 18

made up myelinated axons, FEW cell bodies

brain: under brain
spine: superficial
- divided into dorsal, ventral, and lateral columns
- has ascending tracts and descending tracts

Question 19

brainstem parts

Answer 19

medulla, pons, midbrain

Question 20

medulla (5)

Answer 20

part of the brain stem: networks for automatic function

breathing, cardiovascular, swallowing, vomiting, has ‘pyramids’ as a crossover region for corticospinal tracts

Question 21

pons

Answer 21

part of brainstem: relay station of autonomic pathways

has some neurons for respiration

Question 22

midbrin

Answer 22

part of brainstem: network for eye movements and hearing

Question 23

5 ex of cranial nerves: OOVGV

Answer 23

1: olfactory - sensory: smell info from nose
2: optic - sensory: visual info from eyes

8: vestibulocochlear - sensory: hearing and equilibrium
9: glossopharyngeal - mixed:
- sensory from oral cavity
- chemoreceptors in blood vessels
- efferent for swallowing
- parotid salivary gland secretion
10: vagus - mixed: sensory and efferent to internal organs, muscles and glands

Question 24

gray matter of the cerebrum: 2 parts

Answer 24

cerebral cortex
basal ganglia
… and limbic system

Question 25

basal ganglia

Answer 25

part of gray matter of cerebrum

involved into control of limb/eye movements and cognitive functions
- help you perform and complete a movement

lesions of basal ganglia = loss of neurons here = contribute to parksinsons and huntingtons

Question 26

cerebral cortex

Answer 26

part of gray matter of cerebrum

contains SENSORY AREAS for perception, MOTOR AREAS to direct movement, and
ASSOCIATION AREAS to integrate information
- 5 parts: frontal, parietal, occipital, temporal and prefrontal cortex

surface is folded, sulci (line) divide the gyrus (thick)

Question 27

thalamus

Answer 27

Relay station: receives afferent sensory & motor info, projects fibers to cerebrum for info processing

Question 28

hypothalamus + 2ex

Answer 28

homeostasis and behavior

1. maintains body temp: shivering/sweating
2. controls body osmolarity: thirst/drinking behavior: secretion of vasopressin

Question 29

pituitary gland

Answer 29

Anterior: secretes hormones

Posterior: secretes neurohormones that are made in the hypothalamus
- ex: oxytocin and vasopressin

Question 30

how do the neurohormones secreted by the pituitary gland lay

Answer 30

cell body of neuron in hypothalamus & synaptic terminal in posterior pituitary

Question 31

pineal gland

Answer 31

secretes melatonin and regulates sleep-wake cycle
- cyclic with day/night via photopreceptors

Question 32

tropic vs trophic

Answer 32

tropic = hormone causes a release of another hormone

trophic = hormone causes growth of something

Question 33

limbic system parts

Answer 33

cingulate gyrus - emotion
hippocampus - learning and memory
amygdala - emotion and memory

Question 34

limbic system location/function

Answer 34

around the brainstem

links higher, cognitive regions of the cerebrum
with more primitive functions
- has centers for emotion, memory & learning

Question 35

cerebellum

Answer 35

= little brain
involved in the control of movement & posture, motor learning, adaptation of body & eye movements

integrates sensory and efferent information to ensure movement is coordinated

Question 36

cerebellum inputs vs outputs

Answer 36

Inputs: from all senses (body, visual, auditory, vestibular)
- receives copies of outgoing commands from the motor cortex

Outputs: sent to cortex via thalamus & to spinal cord via the brain stem for control of movement

Question 37

brocas area vs wernickes area

Answer 37

brocas: expression and vocalization
wernickes: comprehension and integration

Question 38

damage to brocas area vs wernickes area

Answer 38

brocas: expressive aphasia
- comprehension is maintained but lose ability of expression in spoken language

wernickes: receptive aphasia
- expression without meaning is maintained but lose comprehension ability