Nervous System

Question 1

what do nerves do?

Answer 1

allow us to sense out environment - sensory and special senses
allow us to respond appropriately to the environment
reflex functions

Question 2

what are the two anatomical subdivisions?

Answer 2

central nervous system and peripheral nervous system

Question 3

what does the central nervous system include?

Answer 3

brain, spinal cord, central controller

Question 4

what does the peripheral nervous system include?

Answer 4

all the other nerve tissue not within the CNS, spinal nerves, cranial nerves, autonomic nerves, wiring

Question 5

what is a collection of nerve bodies called in the PNS and CNS?

Answer 5

PNS - ganglion

CNS - nucleus

Question 6

what does the myelin sheath do?

Answer 6

increase the speed of conduction along the axon of a nerve

Question 7

what is the function of an axon?

Answer 7

to conduct information away from the cell body

Question 8

what is the myelin sheath produced by?

Answer 8

PNS = Schwann cells 
CNS = oligodendrocytes

Question 9

which direction is the action potential for motor and sensory?

Answer 9

motor (efferent) = towards the body wall, body cavity or organ
sensory (afferent) = towards the brain

Question 10

what is a single nerve fibre called?

Answer 10

an axon

Question 11

what the six modalities an axon can conduct?

Answer 11

somatic sensory function 
somatic motor function 
special sensory function 
visceral afferent function 
sympathetic function 
parasympathetic function

Question 12

what are the four lobes of each cerebral hemisphere?

Answer 12

named according to the cranial bone they lie deep to: frontal, parietal, occipital or temporal

Question 13

what are the two things the cerebral consists of

Answer 13

sulci and gyri

Question 14

how many cranial nerves are there?

Answer 14

12 pairs

Question 15

what are the three cranial fossa?

Answer 15

anterior cranial fossa, middle cranial fossa and posterior cranial fossa

Question 16

when does the spinal cord pass through in the cranium?

Answer 16

foremen magnum

Question 17

what is the spinal cord protected by?

Answer 17

vertebral canal

Question 18

what are the four segment of the spinal cord?

Answer 18

cervical, thoracic, lumbar and sacral/coccygeal

Question 19

what are the two enlargements of the spinal cord?

Answer 19

cervical and lumbosacral

Question 20

in what way does the spinal cord connect to the spinal nerves?

Answer 20

bilaterally

Question 21

how many spinal nerves are there?

Answer 21

31, 8 cervical, 13 thoracic, 5 lumbar, 5 sacral, 1 coccygeal

Question 22

where does the spinal cord end?

Answer 22

at L1/L2 (conus medullaris)

Question 23

how many vertebrae are there?

Answer 23

33, 7 cervical, 12 thoracic, 5 lumbar, 5 sacral and 4 coccygeal

Question 24

how do sensory axons reach the horn of the spinal cord?

Answer 24

sensory axons pass from the spinal nerve into the posterior root then into the posterior rootlets and then in the posterior form

Question 25

how to motor axons reach the spinal nerve?

Answer 25

motor axons pass from the anterior form of the spinal cord into the anterior rootlets then into the anterior root into the spinal nerve

Question 26

what do spinal nerves supply?

Answer 26

the soma (body wall)

Question 27

where are spinal nerves located?

Answer 27

intervertebral foramina

Question 28

from the intervertebral foramina where do spinal nerves connect?

Answer 28

the spinal cord via roots and rootlets or structures of the soma via rami

Question 29

how many spinal nerves is each segment of the body supplied with?

Answer 29

a single pair

Question 30

what are dermatomes?

Answer 30

area of skin supplied by both the anterior and posterior rami of a spinal nerve

Question 31

what are the four nerve plexuses and what do they supply?

Answer 31

cervical plexus C1-C4 anterior rami, posterior scalp, neck wall and diaphragm brachial plexus C5-T1 anterior rami, upper limb lumbar plexus L1-L4 anterior rami, lower limb sacral plexus L5-S4 anterior rami, lower limb, gluteal region and perineum

Question 32

what does the soma include?

Answer 32

head and neck walls, chest walls, back, the diaphragm, abdominal wall, pelvic wall and limbs

Question 33

what are the structure of the somatic nervous system?

Answer 33

skin, fascia, skeletal muscle, skeleton, internal lining of body cavities

Question 34

what is somatic sensation?

Answer 34

sensation felt by the body wall (soma)

Question 35

what sensations are felt by the soma?

Answer 35

coarse touch, fine touch, vibration, proprioception, temperature, pain, thermoreceptors sense temperature, nociceptors sense pain, mechanoreceptors sense the others

Question 36

what is pain felt by the cell wall (soma) described as?

Answer 36

sharp and stabbing pain, well localised

Question 37

where do somatic motor axons go once they cross over the brain stem?

Answer 37

descend to the anterior horn

Question 38

from the anterior horn where are action potentials of somatic motor axons conducted?

Answer 38

within the anterior rootlets, then anterior roots, then into spinal nerves

Question 39

what are spinal reflexes?

Answer 39

extremely rapid involuntary response that misses out pathway to the brain

Question 40

what does the autonomic nervous system include:

Answer 40

viscera e.g. heart, lungs glands smooth and cardiac muscle external lining of organs

Question 41

where can the autonomic nervous systems be found?

Answer 41

internal organs in body cavities, body wall organs, sweat glands, arrestor smooth muscle, arterioles

Question 42

what are organ sensory nerves called?

Answer 42

visceral afferent

Question 43

what are some sensations from the organs to CNS?

Answer 43

touch, temperature, pain (ischaemic, colicky)

Question 44

what is pain felt in the organs described?

Answer 44

dull, achey, nauseating, poorly localised

Question 45

what are motor neurons?

Answer 45

respond to changes in the internal environment, they have a dual motor control , many internal organs have a sympathetic and parasympathetic nerve supply

Question 46

what is the sympathetic division of the ANS?

Answer 46

supplies all the internal organs, body wall organs, arterioles, flight or fight response

Question 47

what happens in the flight or fight response of the sympathetic nervous system?

Answer 47

pupils dilate, heart rate increases, bronchioles dilate in lungs, motility in GI tract is reduced liver releases glucose into the blood, adrenal grands release adrenaline/noradrenaline

Question 48

what is the sympathetic outflow?

Answer 48

passes down the spinal cord, exists spinal cord with T1-L2 spinal nerves, travel to sympathetic chains running the length of the vertebral column, pass into all spinal nerves (anterior and posterior rami, to supply body wall structures), with arteries travel to all head and neck organs and skin, via splanchnic nerves to reach organs

Question 49

what is the parasympathetic division of ANS?

Answer 49

often supplies same internal organs as sympathetic division, does not supply body wall organs or arterioles, rest and digest (return to homeostasis, compliments/opposes the sympathetic system)

Question 50

what happens during rest and digest of the parasympathetic nervous system?

Answer 50

all parasympathetic axons leave the ins via the cranial nerves III,VII,IX & X and via sacral spinal nerves, internal organs (parasympathetic ganglia in head to lacrimal gland and salivary glands. vagus nerve supplies organs of the neck, chest and abdomen sacral spinal nerves carry parasympathetic axons to the handout, pelvis and perineum