CNS and PNS

Question 1

CNS

Answer 1

part of the nervous system which consists of the brain and spinal cord

Question 2

bone

Answer 2

provides a strong rigid structure to protect the brain and spinal cord
cranium - brain, vertebrae - spinal cord

Question 3

meninges

Answer 3

layers of connective tissue covering the brain and spinal cord

Question 4

dura mater

Answer 4

tough and fibrous, attached to the skull closely but not so close fitting on the inside of the vertebral canal

Question 5

arachnoid mater

Answer 5

loose mesh of fibres

Question 6

pia mater

Answer 6

contains many blood vessels, sticks closely to the surface of the brain and spinal cord

Question 7

cerebrospinal fluid structure

Answer 7

• clear watery fluid containing some cells and glucose protein fats salts
• occupies space between middle and inner layers of meninges
• formed from blood, circulates through CNS (cavities in brain and through centre of spinal cord) before reentering blood capillaries

Question 8

CSF function

Answer 8

shock absorber, brain suspended in it, provides nutrients to and removes wastes from CNS

Question 8

cerebrum

Answer 8

• thinking reasoning memory intelligence
• coordinating body’s voluntary activities in response to information from sensory receptors
• highly folded to increase SA

Question 9

convolutions/gyri

Answer 9

rounded ridges formed by folding of cerebral cortex

Question 10

sulci and fissures

Answer 10

shallow/deep downfolds between convolutions in cerebral cortex

Question 11

grey matter made of

Answer 11

neuron cell bodies, dendrites, unmyelinated axons

Question 12

basal ganglia

Answer 12

inner surface, consists of nerve cell bodies associated with control of skeletal muscle, plays a role in initiating desired and inhibiting unwanted movement

Question 13

3 functional areas of cerebral cortex

Answer 13

sensory areas - receives and processes impulses from sensory receptors
motor areas - sends impulses to effectors via efferent pathway
association areas - intellectual, emotional interpret info from senses and make it useful

Question 14

lobes

Answer 14

frontal - thinking, problem solving, emotion, personality
insula - recognition of different senses and emotions, addiction, psych disorders
temporal - processing and linking memories with senses/ auditory
occipital - vision
parietal - every other receptor

Question 15

white matter

Answer 15

myelinated axons, fatty nature of myelin sheath causes white colour

Question 16

tracts

Answer 16

myelinated nerve fibres between cerebral cortex and basal ganglia, make up white matter
- connect various areas of cortex within same hemispheres
- carry impulses between right and left hemispheres
- connect cortex to other parts of brain and spinal cord

Question 17

nervous system

Answer 17

system involved with the control and coordination of the body

Question 18

corpus callosum structure

Answer 18

wide band of nerve fibres that lie underneath the cerebrum at the base of the longitudinal fissure

Question 19

corpus callosum function

Answer 19

nerve fibres in the corpus callosum cross between 1 cerebral hemisphere to the other so there is communication between the 2 hemispheres

Question 20

cerebellum structure

Answer 20

under the rear of the cerebrum, surface is folded into a series of parallel ridges

Question 21

cerebellum function

Answer 21

controls posture, balance, fine coordination of movement, receives sensory info from inner ear about posture and balance, and stretch receptors in skeletal muscles for info about length of muscles
all functions take place below conscious level, nerve impulses do not originate from it, can still move, jerky uncontrolled spasmodic movements

Question 22

hypothalamus function

Answer 22

maintains homeostasis (constant internal environment), regulates autonomic, food water intake temp secretion of hormones and part of endocrine system

Question 23

medulla oblongata stucture

Answer 23

continuation of spinal cord, extends from just above point where spinal cord enters skull

Question 24

medulla oblongata function

Answer 24

automatically adjusts body functions as it contains control centres for basic functions necessary for survival
cadiac - rate and force of heartbeat
respiratory - rate and depth of breathing
vasomotor - diameter of blood vessels
other centres for reflexes like cough sneeze etc
influenced and controlled by higher centres of brain esp hypothalamus

Question 25

spinal cord structure

Answer 25

passes through foramen magnum at base of skull, travels down body to 2nd lumbar vertebra
surrounded by vertebrae, meninges, but outer meningeal layer not closely attached to bone, instead there is a space filled with fat blood vessels connective tissue to provide padding to spinal cord and allow it to move when spine bends
grey matter surrounded by white matter - made of unmyelinated fibres and cell bodies
myelinated bundles of nerve fibres in white matter make up ascending and descending tracts
central canal contains CSF

Question 26

spinal cord function

Answer 26

• ascending/descending: sensory/motor neurons carry impulses up/down spinal cord to/away from brain
• integrates spinal reflexes

Question 27

neuron nerve fibre nerve progression

Answer 27

nerve fibres - axons and dendrites of neurons
nerve fibres held together in bundles of connective tissue, mulitple bundles join together to form nerves

Question 28

PNS

Answer 28

part of the nervous system which connects CNS to receptors effectors glands
- nerve fibres arranged into nerves that arise from brain and spinal cord, carry info to and from CNS

Question 29

cranial and spinal nerves

Answer 29

cranial - mostly mixed nerves (made up of sensory and motor fibres)
spinal - all mixed nerves
each nerve joined to spinal cord by 2 roots
ventral root - axon of motor neuron that has cell bodies in grey matter of spinal cord
dorsal root - axon of sensory neuron
dorsal root ganglion - small swelling in dorsal root, contains sensory neuron cell bodies

Question 30

afferent division

Answer 30

carries impulses to CNS from receptors via sensory neurons
somatic - skin and muscles
visceral - internal organs

Question 31

efferent division

Answer 31

carries impulses away from CNS to effectors

Question 32

somatic and autonomic differences

Answer 32

autonomic/somatic
to glands, heart muscle, involuntary muscles/skeletal muscles
controls body’s internal environment/response to outside environment
acetylcholine and noradrenaline/only acetylcholine at effector
usually involuntary/usually voluntary
2 sets of nerve to target organ (para and sympa)/1 set of nerve to target organ
effect on organ to excite or inhibit/excite organ only
pre and post ganglionic nerve fibres from CNS to effector, synapse at ganglion/1 nerve from CNS to effector, no synapse at ganglion

Question 33

parasympathetic

Answer 33

generally produces responses that maintain the body during relatively quiet conditions

Question 34

sympathetic

Answer 34

tend to produce fight or flight responses to prepare body for strenuous physical activity

Question 35

normal vs threatening conditions

Answer 35

normal: both S and P send out nerve impulses to internal organs to maintain stability of body functions (antagonistic)
threatening: S stimulation becomes dominant to provoke fight or flight response, prepares body for increased activity, increase movement increase alertness, think and act quickly

Question 36

fight or flight response

Answer 36

pupils dilate
airways in lungs dilate, increase rate and depth of breathing
increase rate and force of heart contraction, increase blood pressure
blood vessels dilate heart liver lungs skeletal constrict everything else
liver converts glycogen to glucose, increase blood glucose level
adrenal medulla releases nor and adren, prolonging and intensifying these responses
increase secretion from sweat glands