Lecture 3

Question 2

What impairs/blocks nerve conduction?

Answer 2

cold pressure impairs impulse conduction = interrupts blood circ = no o2
sedatives and anaesthetics block nerve impulses by altering membrane permeability = no Na+ entry = no AP

Question 3

Why do fibers with myelin sheaths transmit signals faster?

Answer 3

nerve impulses jump from node to node

Question 4

What is an example of a poison that blocks nerve impulse?

Answer 4

tetrodoxin - produced by pufferfish

Question 5

What is a synapse?

Answer 5

neurotransmitter chemical crosses gap to transmit signal from one neuron to the next
neurotransmitter binds to receptor on the next neuron

Question 6

What are the two types of synapses?

Answer 6

most neurons communicate via chemical synapses
there are also physical synapses

Question 7

What are the steps to a chemical synapse?

Answer 7

• AP reaches axon terminal
• electrical change opens Ca2+ channels
• vesicles containing neurotransmitter fuse with axon membrane and release transmitter
• neurotransmitter diffuses across synapse to bind to receptors on next neuron
• series of events from before occurs

Question 8

After a synapse what happens to the neurotransmitter?

Answer 8

neurotransmitter is removed from synapse either by diffusion away by reuptake into the axon terminal or by enzymatic break down

Question 9

What are the four classes of neurotransmitters?

Answer 9

AA: glutamate, aspartate, glycine, GABA
Monoamines: catecholamines like dopamine, adrenalin and noradrenalin, seratonin
Acetylcholine
Neuroactive peptides: endogenous opioids, peptides from hypothal/pit gland

Question 10

Where does acetylcholine work?

Answer 10

crosses the neuromuscular junctions
ACh excites the muscle-cell membrane, causing depolarization and contraction of the muscle fibre

Question 11

What happens if ACh is not released?

Answer 11

muscle cannot contract

Question 12

What does cholinesterase do?

Answer 12

breaks down Ach

Question 13

Draw out table of neurotransmitters

Answer 13

slide 14

Question 14

What is the function of serotinin/5-hydroxytryptamine (5-HT)

Answer 14

involved in eating, circadian rhythmicity, neuroendocrine, function sleep, mood, anxiety

Question 15

What is 5-HT synthesized from?

Answer 15

tryptophan

Question 16

What is 5-HT an intermediate of?

Answer 16

transformation of tryptophan to serotonin

Question 17

What is the action of a serotonergic drug?

Answer 17

selective serotonin reuptake inhibitor prolongs the action of 5-HT in the synapse by preventing its uptake

Question 18

What is mucosal 5-HT present in?

Answer 18

entero-chromaffin ccells of the mucosal epithelium triggers persitaltic and secretory reflexes through the activation of enteric and sensory neurons

Question 19

What occurs in birds with lower levels of 5-HT?

Answer 19

feather pecking

Question 20

How many cranial nerves are there?

Answer 20

12 cranial nerves

Question 21

What are the 12 cranial nerves?

Answer 21

1. olfactory
2. optic
3. oculomotor
4. trochlear
5. trigeminal
6. abducens
7. facial
8. auditory
9. glossopharyngeal
10. vagus
11. spinal accessory
12. hypoglossal

Question 22

What are some characteristics of spinal nerves?

Answer 22

leave vertebral column and travel to muscles/sensory receptors they innervate, branching repeatedly as they go

Question 23

What is the difference between afferent and efferent axons?

Answer 23

afferent axons bring information inward, toward CNS
efferent axons send information outward

Question 24

What are the steps of a neural reflex?

Answer 24

receptor neuron receives sensory input, which it sends to the brain for processing, the brain analyzes information and determines the appropriate output:
reflex - sensory input -> integration -> motor output

Question 25

What are reflexes?

Answer 25

rapid, predictable, involuntary responses

Question 26

What parts of the NS are reflexes involved in?

Answer 26

CNS and PNS

Question 27

What is the difference between a somatic and autonomic reflex?

Answer 27

somatic - skeletal muscles activated autonomic - regulate body function = smooth muscles, glands etc.

Question 28

What are the 5 elements of a two neuron reflex arc?

Answer 28

1. sensory receptor 2. effector organ 3. sensory neuron 4. motor neuron 5. integration center: spinal cord and or interneurons between sensory and motor neurons

Question 29

What are the steps to a patellar reflex in cats and dogs?

Answer 29

1. sensory fiber is stimulated by the tendon hammer 2. impulse travels via the sensory nerve to the ventral horn in the grey matter of the spinal cord 3. it synapses with the motor neuron whcih affects a muscular contraction

Question 30

What is a withdrawal reflex?

Answer 30

three neuron reflex - limb withdrawn from painful stimuli, interneuron involved

Question 31

Do all withdrawal reflexes result in pain?

Answer 31

no

Question 32

How can electronic feeders be used for cognitive enrichment in pigs?

Answer 32

pigs trained to learn the link between sound given by electronic feeder and a feed reward, can reduce aggression

Question 33

What are the components of the cerebral hemisphere?

Answer 33

cortex and basal nuclei

Question 34

What is the function of the cortex?

Answer 34

gray matter, cerebrums outer layer, localizes and interprets sensory inputs, control voluntary and skilled skeletal muscle activity, acts in intellectual and emotional processing

Question 35

What is the function of the basal nuclei?

Answer 35

islands of grey matter, buried deep within the white matter of the cerebral hemispheres, subcortical motor centers help control skeletal muscle movements

Question 36

What is the result of malfunction of basal nuclei?

Answer 36

huntington or parkinsons disease

Question 37

What is the function of the thalamus?

Answer 37

relays sensory impulses to the cortex, relays impulses between the cortex and lower motor systems, involved in memory

Question 38

What is the function of the hypothalamus?

Answer 38

integration of the ANS, regulates body temperature, food intake, water balance, thirst, regulates hormonal output

Question 39

What is the function of the limbic system?

Answer 39

Includes cerebral and diecephalon structures, mediates emotional responses, memory processing

Question 40

What is the limbic system comprised of?

Answer 40

functional group of integrating centres in cerebral cortex, thalamus and hypothalamus hippocampus and amyglada

Question 41

How do smells trigger strong emotions/memories?

Answer 41

olfactory brain parts in the cranial portion of cerebrum, direct connection to areas that are strongly implicated in emotion and memory

Question 42

What are the various structures of the brain stem?

Answer 42

mid brain, pons, medulla oblongata, reticular

Question 43

What is the function of the mid brain?

Answer 43

contains visual and auditory reflex centers, subcortical motor centers, nuclei for cranial nerves

Question 44

What is the function of the pons?

Answer 44

cooperates with medulla to control respiration, relays info from cerebrum to cerebellum

Question 45

What is the function of the medulla oblongata?

Answer 45

relays ascending pathways from skin and proprioceptors, contains nuclei controlling heart and respiratory rate, vomiting etc.

Question 46

What is the function of the reticular formation?

Answer 46

maintans alertness, filters out repetitive stimuli, helps regulate skeletal and visceral muscle activity

Question 47

What is the function of the cerebellum?

Answer 47

processes information from the cerebral cortex, proprioceptors, visual and equilibrium pathways, responsible for proper balance and posture

Question 48

What are the meninges?

Answer 48

three tissue membranes that cover and protect the CNS dura mater arachnoid mater pia mater

Question 49

What is the dura mater?

Answer 49

the outermost layer - is a double layered membrane around the brain and single layered around spinal cord

Question 50

What is the arachnoid mater?

Answer 50

the middle layer, has web like features

Question 51

What is the pia mater?

Answer 51

innermost membrane - delicate and clings tightly to the surface of the brain and spinal cord

Question 52

What is CSF?

Answer 52

watery liquid similar to blood plasma in its content, contains less protein and more vitamin C and different ion composition, forms cushion around the brain and spinal cord and protects against physical blows and other trauma

Question 53

What does the blood brain barrier do?

Answer 53

neurons kept separated from bloodborne substances composed of least permeable capilalries in the whole body bound together by tight junctions all around

Question 54

What can pass through the blood brain barrier?

Answer 54

only water, glucose, and essential AA can pass easily through