structure + function of the NS: L4

Question 1

define

1. ipsilateral
2. contralateral

Answer 1

1. structures on the same side of the body

2. structures of the opposite side of the body

Question 2

Nervous system has 2 main divisions

Answer 2

1. CNS (brain + spinal cord)

2. PNS (cranial nerves, spinal nerves and peripheral ganglia)

Question 3

1. Somatic system

2. Autonomic nervous system : 2 parts

Answer 3

1. connections CNS to voluntary muscles
2. connections CNS to non-voluntary muscles and glands
   - sympathetic system = arousing (activity, expends energy)
   - parasympathetic system = calming (restoration of energy)

Question 4

1. entire nervous system (CNS & PNS) covered by?
2. 3 layers in the CNS
3. what lays between arachnoid mater and pia mater?
4. PNS only

Answer 4

1. meninges
2. • Dura matter = thick outer
     - Arachnoid matter = middle, soft
     - Pia mater = inner, delicate (follows folds of brain tissue)
3. subarachnoid space = fluid
4. 2 protective sheaths, the dura matter and pia matter -> fuse together to form a single layer covering the spinal nerves and peripheral ganglia

Question 5

arachnoid matter contains

Answer 5

major arteries that cover the surface of the brain

Question 6

Neurological disorders such as viral meningitis and meningococcal disease attack what

Answer 6

the meninges and impair the CNS

Question 7

1. average weight of brain
2. CSF, resides in
3. produced in

Answer 7

1. 1400g
2. supports/protects brain, subarachnoid space around outside of brain and spinal cord & fills ventricles
3. choroid plexus located in lateral ventricles ( 1 in each brain hemisphere)

lateral ventricles -> third ventricle -> cerebral aqueduct -> fourth ventricle -> exits via openings into subarachnoid space -> absorbed back into bloodstream via arachnoid villae

Question 8

Ventricles

1. define
2. lateral
3. third
4. cerebral aqueduct
5. fourth

Answer 8

1. linked fluid filled chambers
2. lateral ventricles located within each hemisphere
3. midline of the brain
4. tube connecting the third + fourth
5. sits beneath cerebellum

Question 9

Obstructive hydrocephalus

1. define
2. due to
3. treated

Answer 9

1. CSF accumulates within the ventricles, not reabsorbed into bloodstream. raises pressure inside the skull = damage brain tissue and occlude arteries, permanent damage
2. due to blockage between choroid plexus within the lateral ventricle and the arachnoid villi within the subarachnoid space
3. insert ventriculo-peritoneal (VP) shunt.

Question 10

development of CNS

Answer 10

1. 18 days after conception
2. after 28 days 3 interconnected chambers = forebrain, midbrain and hindbrain
3. tail connected to hindbrain forms spinal cord
4. • chamber of forebrain forms the two lateral ventricles and third ventricle.
     - chamber in midbrain narrows to form the cerebral aqueduct
     - chamber in hindbrain becomes fourth ventricle

Question 11

5 major subdivisions in the fully formed brain

Answer 11

1. telencephalon
2. diencephalon
3. mesencephalon
4. metencephalon
5. myelencephalon

Question 12

neural migration

1. ventricular zone gives rise to the cells of the
2. precursor cells are called ? and become either

Answer 12

1. nervous system

2. founder cells, neurons or glial cells

Question 13

neural migration

1. development of cerebral cortex
2. how do neurons know where to migrate to in the developing brain?
3. apoptosis is?

Answer 13

1. develops from the inside out. first cells from the ventricular zone travel and establish the first later of the cortex -> cells grow through the first later to form a second -> 6 layers are created in this way
2. guided by glial cell called radial glia. These extend fibres outward from the ventricular zone & attack to the surface of the developing cortex. Neurons crawl from the VZ along these radial glial cells to reach their destination
3. when cortical development ceases. Founder cells receive a chemical message that activate self-destruct.

Question 14

Histogenesis of the cortex

1. what determines the layered structure of the mature cortex
2. layers are defined by
3. mature neocortex consists of how many layers?

Answer 14

1. positions to which different types of neurons migrate
2. types of cells and the structures of the neurons present
3. 6

Question 15

1. the forebrain has 2 subdivisions called
2. Telencephalon composed of
3. the hemispheres comprise
4. cerebral cortex
5. cortex consists of
6. beneath the cortex
7. two hemispheres of the cerebrum are
8. the sulci and gyri
9. purpose of the brain

Answer 15

1. • telencephalon and diencephalon
2. 2 cerebral hemispheres which form the cerebrum
3. outer layer = cortex
   inner = basal ganglia and limbic system
4. highly convoluted, deep grooves = fissures, smaller grooves = sulci/ sulcus and gyrus (bulging tissue)
5. cell bodies, dendrites of neurons and glial cells = grey matter 3mm thick
6. axons of the neurons = white matter
7. slightly asymmetrical
8. follow a defined pattern with only modest variations. between them are used to denote landmarks on the surface of the cortex
9. process sensory information to guide movement and control behaviour

Question 16

Cortical development age 4-21

1. neural darwinism
2. which neurons survive
3. how many die, by what method?
4. yellow & red represent
5. blue & purple represent
6. what areas mature first
7. what areas mature later

Answer 16

1. many more neurons are produced during development that needed -> compete to exist
2. ones whose axon makes contact with another neuron - receive a chemical message from the postsynaptic cell that keeps them alive
3. 50%, apoptosis
4. immature areas
5. mature
6. primary motor, somatosensory, primary visual
7. prefrontal, parietal cortex

Question 17

Primary somatosensory cortex

1. define
2. what does it do

Answer 17

1. vertical strip of cortex located immediately posterior to the central sulcus called the postcentral gyrus
2. receives sensory information -> somatotopic map ( different regions of the skin surface represented along the strip)

Question 18

somatotopic map - sensory homunculus

1. amount of cortex allocated is proportional to?
2. what occupies a large amount?

Answer 18

1. its function rather than size

2. lips, mouth, face and hands

Question 19

Primary visual cortex

1. occupies what areas of the brain
2. receives information from
3. different regions of the retina are represented by

Answer 19

1. medial and lateral parts of the occipital cortex (back of brain)
2. retina
3. different areas within the primary visual cortex forming a retinotopic map

Question 20

primary auditory cortex

1. occupies what areas of the brain
2. receives information from
3. different frequencies are represented by

Answer 20

1. superior part of the temporal cortex & sylvian fissure
2. tonotopic map

Question 21

sensory information of the body is represented?

- in audition

Answer 21

• contralaterally -> opposite hemisphere
• each ear sends sensory information to both hemispheres but the connections to the contralateral hemisphere are stronger

Question 22

primary motor cortex

1. define
2. what does it do

Answer 22

1. strip of cortex located anterior to the central sulcus

2. sends signals to control different groups of voluntary muscles. controls muscles contralaterally

Question 23

Define association areas

Answer 23

• parts of the cortex not involved in the initial reception of sensory information or the control of voluntary muscles
• responsible for all other aspects of perception, learning, memory, acting and feeling