Session 2 - intro to nervous system and neuroanatomy

Question 1

cranial

Answer 1

towards the head

Question 2

caudal

Answer 2

towards the ‘tail’

Question 3

rostral

Answer 3

towards the face

Question 4

dorsal

Answer 4

posterior

Question 5

ventral

Answer 5

anterial

Question 6

What makes up the central nervous system (CNS)

Answer 6

brain and spinal cord

Question 7

what makes up the peripheral nervous system (PNS)

Answer 7

cranial nerves, spinal nerves and autonomic nerves

Question 8

somatic vs autonomic

Answer 8

somatic is voluntary and autonomic is involuntary

Question 9

cerebrum- describe overall structure of cerebrum

Answer 9

largest part of brain, compsed on neurones and supporting cells, split into left and right hemispheres which are connected

Question 10

describe cerebral cortex structure

Answer 10

surface is called cerebral cortex (consists of nuerone cell bodies give grey appearance hence grey matter and info is processed here), cortex contains many folds- gyrus (gyri s.) and the grooves between folds are called sulus (sulci s.)

Question 11

describe inner structure of cerebrum hemispheres

Answer 11

within hemispheres: masses of axons (white matter) and info is transmitted here) , collection of cell bodies (nuclei) and look grey in comparison to white matter

Question 12

name the lobes within each cerebrum

Answer 12

frontal (largest sits in anterior positon), parietal, occipital (smallest and sits posteriorly), temporal (all named after bones in skull)

Question 13

the cerebellum- location relating to cerebrum, describe structure

Answer 13

is infereior to posterior part of cerebrum, composed of left and right hemispheres connected, highly folded cortex, cotains white matter and nuclei deep (collection of cell bodies within CNS), attached to brainstem

Question 14

the brainstem- location, main parts, fucntion

Answer 14

3 main parts: midbrain, pons and medulla, sits inferior to cerebrum, anterior to cerebellum, function- relays info , gives rise to most cranial nerves, contains regulatory centres for breathing and consciousness

Question 15

the spinal cord- connected to? purpose, structure

Answer 15

continuos with medulla of brainstem and is protected by vertebral column but is shorter than column and actually ends around L1-L2, neurone cell bodies located within are grey matter (appears like a H in transverse cross-section) these are then surrounded by white matter which contains tracts (bundles of axons that connect different parts of CNS together) however these cannot be seen with naked eye. 31 pairs of spinal nerves are attached to spinal cord and corresponds to a difefrnet segment. They carry info between spinal cord and periphery (muscle and skin)

Question 16

brain ventricles- structure, function

Answer 16

4 ventricles are continuos with each other and are filled with cerebrospinal fluid (CSF) produced by specialised cells, CSF leaves venrtivles through small openings and surrounds brain and spinal cord. Function is: provides nutrient to brain, cushions brain, prevents delicate nerves and vessels being compressed, there is also a narrow CSF-filled channel within spinal cord.

Question 17

the meninges: names of meningeal layers

Answer 17

3 membrane between brain and spinal cord, menegial layers called: dura mater, arachnoid mater and pia mater

Question 18

dura mater- structure

Answer 18

Dura mater: lines inner surface of skull and vertebral column, thick and strong, extensions of dura project into cranial cavity

Question 19

arachnoid mater- structure

Answer 19

deep to the dura, thin and loosley enclose brain and spinal cord

Question 20

pia mater- structure

Answer 20

deep to arachnoid mater, thin and loosely adgere to surafce of brain and spinal cord, cannot be seen with naked eye

Question 21

name the four arteries that supply the brain with blood

Answer 21

left and right internal carotid, left and right vertebral arteries

Question 22

What is the circle of willis

Answer 22

arteries join together to form a circle (example of anastomosis), blood supply to all areas of brain even if an artery is cut off

Question 23

arteries present in brain

Answer 23

cerebral arteries- supply cerebral hemispheres, cerebellar arteries- supply cerebellum, arteries that supply brain stem and spinak cord

Question 24

veins present in brain

Answer 24

deep veins and superficial veins which drain blood from brain, also large veins called dural venous sinuses (enclosed in dura mater)

Question 25

somatic nervous system

Answer 25

somatic- voluntary, has motor (voluntray contraction of skeletal muscle) and sensory components (carries info from peripheral stimuli from sensory receptors in CNS to our concoius perceptions)

Question 26

autonomic nervous system

Answer 26

autonomic- involuntary,
Motor component: smooth muscle, cardiac muscle, glands, in two parts fight or flight: sympathetic , rest and digest: parasympathetic
Sensory component: conveys sensory info about internal environment of argans (viscera) to CNS

Question 27

sympathetic response:

Answer 27

heart rate increases, bronchi dilate, pupils dilate, hairs stand up, sweat glands stimulated, blood supply diverted away from gut and skin and to skeletal muscle,

Question 28

parasympathetic response:

Answer 28

heart rate decreases, bronchi constrict, glabds and gut activity are stimulated, pupils constrict

Question 29

sympaphetic vs parasympathetic

Answer 29

Similarities:
both have 2 neurons in pathways to target organ
both axons leave CNS and synapse with a second neurone whose cell body is located in a ganglion (collection of cell bodies outside CNS).
have visceral efferent nerves (leave CNS) and visceral affereant nerves (come back to CNS)
Differences:
sympatheic first neurone body located T1-L2/3 where as parasympathetic first nuerone body located S2-S4
sympathetic has a short preganglionic axon amd a long post-gaglionic axon where as pararsympathtic has a long pre-ganglionic axon and a short post-ganglionic axon
Sympathetic system is far more widely distributed than parasympathetic

Question 30

sensory component of autonomic nervous system-

Answer 30

sensory autonomic fibres (also known as afferent fibres) bring info back into CNS along sympathetic and non-sympathetic pathways but usually bypass conciuos.
1.convey nformation about internal environment and elicit a reflex (doesn’t reach consciousness) e.g. high bp
2. convey info about stretch, distension and spasm in viscera which may cause pain (does reach consciousness)

Question 31

cranial nerves- name them :)

Answer 31

arise from cerebrum and brain stem, 12 pairs:
olfactory tract
optic nerve
oculomotor nerve
trochlear nerve
trigeminal nerve
abducens nerve
facial nerve
vestibulocochlear nerve
glossopharyngeal nerve
vagus nerve
accessory nerve
hypoglossal nerve

Question 32

cranial nerves- where do they go? what fibres do they contian?

Answer 32

cranial nerves leave CNS and travel to periphery so are part of peripheral nervous system (except nerve I and II), they exit skull by leaving out through holes in base called foramina, some cranial nurves are purely sensory or motor or a mix of both, some serve senses and some carry parasympatahtic fires- NO sympathetic fibres present

Question 33

Spinal nerves- where are spinal nerves corrsponfing segment? what fibres do they contain?

Answer 33

31 pairs of spinal nerves and each pair corresponds to a segment: 8 pairs in cervical (C1-C8), 12 pairs in throax (T1-T12), 5 pairs in lumbar (L1-L5), 5 pairs in sacral (S1-S5), 1 pair in coccygeal (Co1)

8,12,5,5,1

spinal nerves are mixed and carry a mix of somatic motor, somatic sensory and sympathetic, spinal nerves pass between each vertabrae through intervertebral foramina

Question 34

somatic motor fibres- location in vertebra?

Answer 34

cell bodies of motor neurones located in ventral horn of spinal cord, leave cord via ventral motor root, these motor fibres stimulate voluntary contraction of skeletal muscle

Question 35

somatic sensory fibres- location in vertebrae?

Answer 35

cell bodies of peripheral sensory neurones are loacted in dorsal root ganglia (appear as small sweelings on dorsal root), neurones have 2 processes - one peripherally into spinal nerve and 1 centrally into dorsal horn

Question 36

dermatomes and mytotomes

Answer 36

dermatome- area of skin innervated by a single spinal nerve
myotome- group of muscles innervated by single spinal nerve