L17

Question 1

explain neurons

Answer 1

• Brain has 85 billion
  
  • 200000 inputs + outputs/ neuron
  • Afferent (come in) + efferent (goes out)
  • Electrically excitable
    
    • Fast conduction

Question 2

what are the 3 neurons structures + draw them

Answer 2

○ Multipolar (motor)
○ Bipolar (retina)
○ Unipolar (sensory)

REFER TO ONENOTE

Question 3

explain sensory neurons

Answer 3

○ Pain, touch, pressure
○ Generates AP in response to stimuli
○ Unipolar
Central axon passes into spinal cord

Question 4

explain Interneurons

Answer 4

○ Entirely in CNS
○ 99% of all nerve cells
○ Integrate peripheral info.
Mostly inhibitory

Question 5

explain efferent neurons

Answer 5

○ Cell bodies in CNS
○ Many dendrites + synaptic inputs
○ Connect to glands/muscles
- Motor

Question 6

explain neural circuits

Answer 6

• Function group of neurons, process specific types of info.
  
  • E.g. Amplifies sensory signals
    More effective stimulation/inhabitation

Question 7

explains grey vs white matter

Answer 7

• Neuronal bodies clustered together in CNS (nucleus) and PNS (ganglion)
  
  • Axons also clustered in tracts (CNS) and nerves (PNS)
  • White coloration from myelination, rest is grey
    In spinal cord, white is on outside, in brain, on inside

Question 8

explain the organisation of nervous system

Answer 8

• Central nervous system
  ○ Brain + spinal cord
  
  • Peripheral nervous system
    ○ Afferent
    § Sensory stimuli
    § Enteric stimuli
    ○ Efferent
    § Somatic- motor neurons to skeletal muscle
    § Autonomic
    Sympathetic + parasympathetic- smooth + cardiac muscle, glands

Question 9

explain the central nervous system, and the function of sensory, integrative, and motor neurons

Answer 9

• Made up of brain + spinal cord
  
  • Function
    ○ Sensory
    § Sense stimuli, sends message to integrative
    ○ Integrative
    § Analyses incoming info., makes decision to respond
    ○ Motor
    Carries out response

Question 10

describe the function of the brain stem, cerebellum, diencephalon, cerebrum

Answer 10

○ Brain stem
§ Primitive function
○ Cerebellum
§ Body position + motor coordination
§ Outer layer of cerebellar cortex
○ Diencephalon
§ Homeostasis
§ Primitive sensory processing
○ Cerebrum
§ Voluntary movement
§ Sensory perception
§ Language
§ Personality
Outer layer of cerebral cortex

Question 11

label the the brain

Answer 11

REFER TO ONENOTE

Question 12

3 things the protect brain

Answer 12

• Cranial bones
  
  • Cranial meninges
    ○ Dura, arachnoid, pia matter
  • Cerebrospinal fluid
    Found in ventricles, central canal, subarachnoid space, in around + inside brain and spinal cord

Question 13

explain blood flow to the brain

Answer 13

• Via vertebral + ceratoid arteries
  
  • Flows back to the heart via jugular veins
    Blood flow is constant at 15% of cardiac output

Question 14

what are 2 requirements of the brain

Answer 14

• Brain uses about 20% of bodies oxygen supply
  
  • But is only 2% of body weight
  • Interruptions of oxygen supply results in weakness + permanent damage within minutes
  • Glucose deficiency also leads to mental confusion, dizziness, unconsciousness
    So blood flow is HIGHLY regulated

Question 15

explain the blood brain barrier

Answer 15

• Protects brain cells form harmful substances/pathogens
  
  • Is a selective barrier, prevents passage of substances from blood into brain
  • Can prevent entry of therapeutic drugs
  • Injury to brain can cause breakdown of bbb, allowing passage of harmful material
  • Created by fibrous astrocytes

Question 16

explain cerebrospinal fluid

Answer 16

• Clear liquid
  
  • About 150ml
  • Protects brain + spinal cord against chemical + physical damage (shock absorber)
  • Carries oxygen, glucose ect. From blood to nervous tissue cells
  • Classified as ‘transcellular’ fluid made in the brain, from plasma
  • Circulates both around + inside CNS, via ventricles
    Moved around by ependymal cells (neuroglia) that have cilia