CNS and PNS

Question 1

where are the respiratory centres in the brain?

Answer 1

in the brainstem: medulla and pons

Question 2

which brainstem centres generate the respiratory pace?

Answer 2

respiratory rhythmicity centres in the medulla oblongata

Question 3

what are the little branches across the subarachnoid space called?

Answer 3

arachnoid trabeculae

Question 4

what are the outer dura mater and the inner dura mater also known as?

Answer 4

outer dura mater = endosteal layer

inner dura mater = meningeal layer

Question 5

what is another name for the epidural space?

Answer 5

the dural sinus

Question 6

what are the three layers of the meninges called?

Answer 6

dura mater
arachnoid mater
[subarachnoid space (CSF)]
pia mater

Question 7

which branch of the ANS has long pre-ganglionic fibres and short post-ganglionic?

Answer 7

parasympathetic

Question 8

how is the autonomic nervous system divided?

Answer 8

sympathetic nervous system

parasympathetic nervous system

Question 9

which branch of the ANS has short pre-ganglionic fibres and long post-ganglionic fibres?

Answer 9

sympathetic

Question 10

in which branch of the ANS do pre-ganglionic fibres release acetylcholine?

Answer 10

both

Question 11

in which branch of the ANS do the post-ganglionic fibres release noradrenaline?

Answer 11

sympathetic

Question 12

in which branch of the ANS do the post-ganglionic fibres release acetylcholine? what is its effect?

Answer 12

parasympathetic

may increase or decrease activity of effect (slows heart rate; increases motility)

Question 13

what is special about cranial nerve x?

Answer 13

it’s the only non local cranial nerve

Question 14

describe the blood supply to the brain

Answer 14

two internal carotid arteries
two vertebral arteries - join to form basilar artery

all join to form the arterial circle of Willis

Question 15

identify the neuroglia (glial cells) of the CNS

Answer 15

ependymal cells
astrocytes
oligodendrocytes
microglia

Question 16

between which two layers of the meninges is the CSF?

Answer 16

CSF is in the subarachnoid space between the arachnoid mater and the pia mater

Question 17

which glial cell protects the CNS from chemical and hormones circulating in the blood?

Answer 17

astrocytes maintain the blood brain barrier

Question 18

what three things protect the brain from mechanical forces?

Answer 18

cranium bones, cranial meninges, CSF

Question 19

which neuroglia in the CNS myelinated and stabilise axons?

Answer 19

oligodendrocytes.

each one will myelinated several axons; each axon is myelinated by several oligodendrocytes

Question 20

describe the neurilemma

Answer 20

the outer surface of a Schwann cell when it covers an axon is called the neurilemma

Question 21

what are the anatomical divisions of the nervous system?

Answer 21

the CNS and the PNS

Question 22

what are the functional divisions of the PNS?

Answer 22

the afferent division brings sensory information to the CNS from receptors in peripheral tissues and organs

the efferent division carries motor commands from the CNS to muscles, glands and adipose tissue (effectors)

SAME

Question 23

what are the components of the efferent division of the PNS and what effectors do they regulate?

Answer 23

the somatic nervous system(controls both voluntary and involuntary contractions of the skeletal muscles) and the autonomic nervous system (regulates smooth muscle, cardiac muscle, glandular secretions and adipose tissue at the subconscious level)

Question 24

how is the ANS divided?

Answer 24

into the sympathetic and parasympathetic divisions

Question 25

name the effectors of the ANS

Answer 25

smooth muscle cardiac muscle glands adipose tissue

Question 26

which neuroglia appear in increased numbers in a person with a brain infection?

Answer 26

microglia - they are small mobile cells that remove cellular debris, wastes and pathogens by phagocytosis they're related to macrophages and monocytes

Question 27

describe the function of ependymal cells

Answer 27

they form an epithelium known as the ependyma which lines a fluid filled passageway in the CNS it's known as the central canal in the spinal cord and the ventricles in the brain the cavity is filled with CSF; ependymal cells help to produce, monitor and circulate the CSF

Question 28

what is the role of astrocytes besides maintaining the blood-brain barrier?

Answer 28

creating a 3D framework for the CNS and regulating the interstitial environment

Question 29

contrast the white matter and grey matter in the CNS

Answer 29

white matter dominated by myelinated axons grey matter is areas dominated by cell bodies, dendrites, unmyelinated axons

Question 30

what are the neuroglia of the peripheral nervous system? what are their roles?

Answer 30

satellite cells - surround neuron cell bodies in ganglia and regulate the environment (like astrocytes in the CNS) Schwann cells - myelinate peripheral axons or else wrap around an axon to protect it without myelinating it

Question 31

what type of compounds can easily cross the blood-brain barrier?

Answer 31

lipid soluble compounds (oxygen, carbon dioxide, lipids, ammonia)

Question 32

define nerve fibre

Answer 32

the axon of a neuron

Question 33

why is a CNS neuron not usually replaced after it is injured?

Answer 33

most CNS neurons lack centrioles and cannot divide

Question 34

is the grey matter on the outside or the inside of the brain?

Answer 34

the outside

Question 35

where are most interneurons found?

Answer 35

in the CNS

Question 36

define soma

Answer 36

neuron cell bodies

Question 37

what percentage of neurons do interneurons make up?

Answer 37

about 99% of all neurons

Question 38

what does grey matter do?

Answer 38

processes information grey matter = computer white matter = cables

Question 39

what are the major components of the CNS?

Answer 39

the brain and spinal cord

Question 40

what is the role of interneurons?

Answer 40

they're responsible for the analysis of sensory inputs and coordination of motor outputs

Question 41

what is a sensory neuron also known as?

Answer 41

an afferent neuron

Question 42

in which part of the nervous system does Wallerian degeneration occur and what does it involve?

Answer 42

the PNS involves the repair of damaged nerves but often fails to restore full function limited regeneration can also occur in the CNS but it's more complicated there

Question 43

what is a reflex?

Answer 43

a rapid, automatic response triggered by specific stimuli

Question 44

define spinal reflex

Answer 44

spinal reflexes are controlled in the spinal cord and can function without any input from the brain

Question 45

how many pairs of nerves does a typical spinal cord have?

Answer 45

31

Question 46

where does the spinal cord end?

Answer 46

between vertebrae L1 and L2 (cord is not as long as the vertebral column)

Question 47

describe the gross anatomical features of a cross section of the spinal cord

Answer 47

1. the anterior median fissure - a deep groove along the anterior surface 2. the posterior median sulcus - a shallow longitudinal groove 3. white matter - dominated by myelinated axons 4. grey matter - cells bodies of neurons, neuroglia, unmyelinated axons (deep to the white matter) 5. the central canal (containing CSF) 6. a posterior root of each spinal nerve (contains the axons of sensory neurons) 7. the anterior root of each spinal nerve (contains the axons of motor neurons) 8. posterior root ganglia (contains cell bodies of sensory neurons) 9. spinal nerves (containing the axons of sensory and motor neurons)

Question 48

where do sensory and motor neurons become a single nerve?

Answer 48

distal to each dorsal root ganglion

Question 49

via which root does the motor nerve exit the spinal cord?

Answer 49

ventral or anterior root (at the front)

Question 50

where are most of the cell bodies of most motor neurons found?

Answer 50

in the CNS

Question 51

via which root does sensory information enter the spinal cord?

Answer 51

the dorsal (posterior) root