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Neuroscience Flashcards

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Biology 101 flashcards
1
Q

Name 3 divisions of the NS

A

Central NS
Peripheral NS
Enteric NS

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2
Q

What does the CNS consist of?

A

Brain and Spinal Cord

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3
Q

What does the PNS consist of?

A

Nerves and cell bodies protruding from the brain and spinal cord.

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4
Q

What is the Enteric nervous system?

A

Often percieved as being the PNS, the enteric nervous system is a system of interneurones, motorneurones and afferent neurones which form complexes called Plexuses that surround the gastrointestinal tract.

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5
Q

What is viscera?

A

The internal organs and main cavities of the body.

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6
Q

How many pairs of peripheral nerves are there?

A

43 pairs.

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7
Q

What is a neuron? what does it contain? what does it not contain?

A

Neurons are bundles of individual nerve processes. They contain axons. They DONT contain dendrites are dendrites are specialized for receiving inputs. They also don’t contain neuronal cell bodies.

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8
Q

What does it mean if a nerve is defined as being Mixed?

A

It contains both Sensory and Motor neurons.

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9
Q

Describe the composition of a nerve.

A

It begins with nerve fibers, each nerve fiber is surrounded by a coating called the Endoneurium. These nerve fibers are bundled together into Fascicles. individual fascicles bundle are surrounded by a protective coating called the Perineurium. Fascicles are bundled together and surrounded by another protective sheath called the Epineurium. The epineurium also encloses the fascicles with blood vessels.

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10
Q

Name the cranial nerves. in order 1 to 12.

A 
1 - Olfactory
2 - Optic
3 - Oculomotor
4 -Trochlear
5 - Trigeminal
6 - Abducens
7 -  Facial
8 - Vestibulocochlear
9 - Glossopharyngeal
10 - Vagus
11 - Accessory
12 - Hypoglossal
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11
Q

What % of PNS outflow id the vagus nerve responsible for?

A

80%

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12
Q

What is the function of an interneuron?

A

Act as relay neurons. Allow commuication between sensory and motor neurons and the CNS.

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13
Q

What is the function of a Motor neuron?

A

Carry impulses from the Brain/Spinal cord to the Muscles/Glands.

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14
Q

What is the function of a sensory neuron?

A

Carry sensory information to the brain/spinal cord.

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15
Q

How many spinal nerves are there?

A

31 pairs

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16
Q

What are RAMI?

A

Where the spinal cord nerves project out of the spine and begin to branch.

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17
Q

What is a dermatome?

A

An area of the skin which is mainly supplied by a single spinal nerve.

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18
Q

Is the somatic (afferent) division voluntary of involuntary? and what is it associated with?

A

Voluntary. Associated with pain.

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19
Q

Whats the difference in the transmission of signals in Somatic and Autonomic efferents?

A

In somatic efferents, the signal travels down motor axons from the spinal cord straight to the muscle.
In Autonomic efferents, the signal travels down motor axons to a synapse with another cell in a ganglion, this cell then innervates the muscle/gland.

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20
Q

In the Autonomic efferent pathway, what is the difference in the myelination of axons?

A

The axons between the spinal cord and the ganglion are myelinated. The axons between the ganglion and the muscle/gland are NOT myelinated.

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21
Q

What are the sympathetic ganglia near the spinal cord called and what do they form?

A

Paravertebral ganglia and form the sympathetic chain.

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22
Q

What are sympathetic ganglia close to the target called?

A

Collateral ganglia.

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23
Q

How many synapses can a single preganglionic sympathetic axon innervate?

A

20

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24
Q

How many synapses can a single preganglionic parasympathetic axon innervate?

A

4

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25
Q

Are sympathetic preganglionic neurones short or long?

A

Short

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26
Q

Are parasympathetic preganglionic neurones short or long?

A

Long

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27
Q

What do the sympathetic and parasympathetic NS’ have in common?

A

They both use Ach and N2 receptors.

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28
Q

Are parasympathetic post ganglionic neurons Adrenergic or Cholinergic?

A

Cholinergic. They use mAChR - muscarinic acetyl choline receptors. These are G-protein receptor complexes.

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29
Q

What is trepanning?

A

Opening up the skull.

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30
Q

Who studied brain tumors between 500-200BC?

A

Huang Ti

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31
Q

Who thought consciousness came from the heart?

A

Aristotle

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32
Q

Who thought conciousness came from the brain?

A

Plato

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33
Q

Who was one of the first to use animals as model organsims?

A

Galen

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34
Q

Name 2 Islamic Scholars in neuroscience/

A

Al-Hazen and Al-Zahrawi

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35
Q

Who studied the giant squid axon? And what species was it? And what did they use it for?

A

Hodgkin and Huxley. Loligo pealei squid. They used a micropipette to flush out ions allowing the determination of ion flows during action potentials. This allowed them to see what ions were inside and outside the membrane.

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36
Q

Who first pointed out the giant squid axon?

A

J Z young

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37
Q

What organism is used to study apoptosis?

A

C. Elegans

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38
Q

Who first discovered how fast electrical stimulation traveled across a nerve?

A

Helmholts.

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39
Q

Who discovered how Axons grow?

A

Ross J Harrison

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40
Q

Who investigated how nerves pathfind and how did he do it?

A

Sperry. He cut the optic nerve and turned it upside down in a cat, it grew back but altered the cats vision as it saw things 180 degrees differently.

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41
Q

What 3 scientists studied on chicks?

A

Victor hamburger. Rita Levi-Montalcini and Nichole Le douarin.

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42
Q

Who studied imprinting in chicks?

A

Konrad Lorenz

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43
Q

Who studied passive avoidance training in chicks?

A

Steven Rose

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44
Q

Who names the Autonomic Nervous System?

A

Langley.

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45
Q

Who researched engram (the part of the brain that stores memory) in rats?

A

Lashley.

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46
Q

Name and describe 2 Neural tube defects.

A

Spina bifidia - The neural tube doesn’t close properly. This can lead to improper formation of the spinal cord.
Anencephaly - Occurs during the first few weeks of embryonic development and results in a the neural tube failing to close. This results in offspring being born without a forebrain.

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47
Q

Why is follic acid useful during pregnancy?

A

It acts as a coenzyme to prevent neural tube defects. During embryonic development, the cells require follic acid to grow cells, tissues and organs.

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48
Q

What are the 3 primary brain vesicles? and what do they become?

A

Prosencephalon - Forebrain
Mesencephalon - Midbrain
Rhombencephalon - Hindbrain.

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49
Q

What does the caudal neural tube give rise to?

A

Spinal cord

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50
Q

What are the secondary brain vesicles of the forebrain?

A

The prosencephalon differentiates into the telencephalon and the optic vesicles which both sprout off a structure called the diencephalon.

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51
Q

What does the hindbrain differentiate into?

A

Metencephalon and myelencephalon.

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52
Q

What does the metencephalon and myelencephalon become?

A
  • The metencephalon (rostral half) becomes the Pons and cerebellum.
  • The myelencephalon (caudal half) becomes the Medulla oblongata.
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53
Q

How do the optic nerves and retinas form?

A

They form from the optic vesicles. The optic vesicles grow and invaginate to become the optic stalks and further to become the optic stalks. These later become the optic nerves and retinas for both eyes.

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54
Q

What does the Telencephalon form and how does it do it?

A

The telencephalon forms the two cerbral hemispheres. The telencphalic vesigles grow posteriorls so they lie lateral to the diencephalon and begin to encase it. They continue to grow laterally and fuse at the top and front (dorsal and rostral).

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55
Q

Where do the olfactory bulbs differentiate from?

A

Telencephalon. They sprout off the ventral surfaces off the newly formed cerebral hemespheres and give rise to the olfactory bulbs.

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56
Q

Where do the hypothalamus and thalamus derive from?

A

Diencephalon

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57
Q

What do the bundles of axons and neurones in the developing forebrain give rise to?

A

Cortical white matter.
Corpus Callosum
Internal Capsule.

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58
Q

What is the function of the cortical white matter?

A

Contains all the axons that run to and from the neurons in the cerbral cortex.

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59
Q

What is the function of the corpus callosum?

A

It is continuous with the white cortical matter and acts as an axonal bridge linking the cortical neurons of the two cerebral hemispheres.

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60
Q

What is the function of the internal capsule?

A

It is continuous with the white cortical matter and links the cortex to the brain stem, particularly the thalamus.

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61
Q

What does the midbrain differentiate into?

A

It doesn’t differentiate much. The dorsal surface of the mesencephalon differentiates into the tectum. The ventral surface of the mesencephalon differentiates into the tegmentum.

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62
Q

What does the tectum differentiate into?

A

The inferior and superior colliculi.

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63
Q

What is the role of the superior colliculus?

A

Responsible for receiving direct input from the eye and controls eye movement. Often referred to as the optic tectum.

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64
Q

What is the role of the inferior colliculus?

A

Receives sensory information from the ear and relays auditory information to the thalamus.

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65
Q

What 2 nerves bundle with the superior colliculus?

A

Oculomotor (3) and Trochlear (4)

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66
Q

What is the role of the cerebellum?

A

Coordination of body movements.

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67
Q

What is the role of the pons?

A

Acts as a switchboard, connecting the cerebral cortex to the cerebellum.

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68
Q

How many ventricles are there in the brain?

A
  1. 2 lateral ventricles, third ventricle and fourth ventricle.
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69
Q

Where are the brain ventricles located?

A

The third ventricle is located in the diencephalon (between the left and right thalamus).
The fourth ventricle is located at the back of the pons and the upper half of the medulla in the hind brain.
The two lateral vesicles are the biggest. They have a C shape and span through the parietal and frontal lobe. They finish at the interventricular foramina.

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70
Q

What is the interventricular formina?

A

The area of the brain where each lateral ventricle connects to the third ventricle.

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71
Q

What do the brain ventricles contain? and what is its function?

A

Cerebrospinal fluid (CSF) this protects the brain

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72
Q

What is the role of the cerebral aqueduct?

A

Connects the third ventricle to the fourth ventricle.

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73
Q

What is the spinal cord encased in?

A

A bony vertebrae called the spinal canal. The spinal canal is made up of arches of bone that connect to the underside of vertebral bodies.

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74
Q

What are the 3 meninges? outer to inner.

A

Dura matter, Arachnoid and Pia mater.

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75
Q

What does the dura form?

A

The dura is a tough, inelastic bag sround the brain and spinal cord. it splits into two forming the endosteal layer and the meningeal layer, inbetween is the dura sinus.

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76
Q

What is a subdural hematoma?

A

Where a blood vessel passing through the dura ruptures. Treated by drilling a hole into the skull and draining the blood.

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77
Q

Which meningies are separated and which aren’t?

A

The Dura and Arachnoid are always touching. The Arachnoid and the Pia are separated by a fluid filled space containing cerebrospinal fluid called the subarachnoid space.

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78
Q

What is the blood brain barrier formed by?

A

Capillary endothelial cells.

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79
Q

What 3 areas does the Cerebrospinal fluid flow?

A

Cerebral aqueduct.
Brain ventricles.
Subarachnoid space.

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80
Q

How can CSF be sampled?

A

Using lumbar puncture. A needle is inserted between the third and fourth lumbar vertebrae.

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81
Q

What is the blood brain barrier?

A

A highly selectively permeable physiological barrier between the blood and the cerebrospinal fluid in the brain. Consists of capillary endothelial cells, tight junctions and astrocytes.

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82
Q

What are ganglia/nuclei?

A

Clusters of neurons.

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83
Q

What is the term used when there is crossing over of sensory and motor pathways?

A

Decussation.

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84
Q

Give an example of where decussation is seen?

A

Corticospinal tract. Occurs near where the medulla joins the spinal cord each pyramidal tract crosses causing pyramidal decussation.

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85
Q

Where is the site of origin for many cranial nerves?

A

Brain stem.

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86
Q

What 3 structures is the brainstem comprised of?

A

Medulla Oblongate
Pons
Mesencephalon

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87
Q

What is the function of the Medulla Oblongata?

A

Control of the cardiovascular and respiratory systems.

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88
Q

Name 4 major features of the Medulla Oblongata.

A

Fibre tracts.
Nuclei (ganglia)
Olives
Nerve roots.

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89
Q

What is the function of nuclei (ganglia) in the Medulla Oblongata?

A

These are clusters of neurones responsible for channeling information to the respiratory and cardiovascular systems.

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90
Q

What is the function of Olives in the Medulla Oblongata?

A

Are swellings called olivary nuclei and send axons to the cerebellum.

91
Q

Where do cranial nerves originate in the Medulla Oblongata?

A

Nerve roots.

92
Q

What structures are contained in the Pons and what are their function?

A

Peduncles. Function is to send information into and out of the cerebellum.

93
Q

Describe the structure of the cerebellum.

A 
Is a multitubulous structure (has folds), these foldsa are called Folia.
Consists of 4 layers:
- Molecular Layer
- Purkinje cell layer
- Granular layer
- White matter
94
Q

What is the arbor vitae?

A

The white matter layer of the cerebellum. Forming a tree like structure.

95
Q

What neurotransmitter is formed in the substantia nigra?

A

Dopamine.

96
Q

What is the function of the thalamus?

A

It receives sensory information, processes it and sends it off to higher brain centers. Acts as a relay center. Smell is the only exception.

97
Q

What hormones does the pineal gland secrete?

A

Melatonin and serotonin.

98
Q

What are the 6 lobes of the brain?

A 
Frontal
Parietal
Temporal
Occipital
Limbic
Insula
99
Q

How many layers are there of the neocortex? What are they, in order?

A 
7.
Molecular layer
external granular layer
external pyramidal layer
internal granular layer
internal pyramidal layer
fusiform layer
white matter
100
Q

What is Broca’s Aphasia and how does it occur?

A

Occurs due to damage in the left frontal lobe. Results in expressive aphasia. Impared speech, grammer, syntax and word structure.

101
Q

What is Wernicke’s Aphasia and how does it occur?

A

Posterior temporal lobe damage. Results in receptive aphasia, the use of inappropriate words but spoken fluently.

102
Q

Name two techniques used to map the brain in the modern era.

A

PET Scanning

MRI Scanning.

103
Q

Name 3 factors that the left hemisphere is involved in.

A

Speech
Calculation
Analysis

104
Q

Name 3 factors that the right hemisphere is involved in.

A

Spatial
Conceptual
Artistic.

105
Q

How does lateralisation occur in the brain?

A

Occurs as a result of differential hemisphere gene expression during development. But can also be due to environmental factors.

106
Q

What does the basal ganglia consist of?

A

Caudate and Putamen (Striatum)
Globus pallidus
Subthalamic nucleus
Substantia nigra

107
Q

What are association fibres?

A

Fibres that link areas within a hemisphere. Such as Arcuate fibres and longitudinal fasiculi.

108
Q

What are commissural fibres?

A

Fibres that connect between hemispheres. Such as the Corpus Callosum and anterior commissure

109
Q

What are projection fibres?

A

Fibres which project away from the CNS.

110
Q

What is the limbic system associated with?

A

Memory, emotion and motivation.

111
Q

What does the limbic system consist of?

A 
Limbic lobe
Hippocampus 
Amygdala
Thalamus
Hypothalamus
112
Q

What is the difference between golgi type 1 and golig type 2

A

Golgi type 1 have long axons.

Golig type 2 have short axons.

113
Q

Give and example of a unipolar neuron.

A

Dorsal root ganglia

114
Q

Give an example of a bipolar neuron

A

Retinal bipolar cell.

115
Q

Give an example of a multipolar cell

A

Motor neurones in the symmetrical dendritic field.

Purkinje cells in the planar dendritic field.

116
Q

Why are pyramidal cells in the cerbral cortex fuzzy?

A

Because they’re convered in dendritic spines.

117
Q

What are the most common neuron type in the brain?

A

Cerebellar granule cells.

118
Q

Give an example of an anaxonic cell.

A

Olfactory granule cells.

119
Q

What are dendrodendritic synapses?

A

Synapses between one synapse and another.

120
Q

Name and define 3 classifications of glial cells.

A

Macroglia (big)
Microglia (small)
Ependyma (ependymal cells, form the lining membranes between the brain and fluid filled spaces.)

121
Q

What is an astrocyte?

A

A star shaped glial cell of the CNS.

122
Q

Name two types of astrocyte.

A 
Fibrous types (contain lots of filaments in their composition)
Protoplasmic ( Don't have a lot of filaments in their composition)
123
Q

Name two specialised astrocytes.

A

Retinal muller cells

Radial clia

124
Q

What can be used to stain astrocytes?

A

Antibodies.

125
Q

Name 3 roles astrocytes are involved in.

A

Spatial buffering
Transmitter uptake
Glucose metabolism.

126
Q

What is spatial buffering and why is it useful?

A

When neurons undergo action potentials they release potassium. The potassium concentration of the ECM therefore increases dramatically. High potassium concentrations in the ECM can disrupt cell function. Astrocytes are highly permeable to potassium therefore they act as a functional syncytium to regulate the potassium concentration of the ECM. An example is in the retina as muller cells take up ECM potassium to allow the photoreceptors to function.

127
Q

What is the most important excitatory transmitter in the brain?

A

Glutamate

128
Q

What is a major inhibitory transmitter in the brain?

A

GABA

129
Q

Describe transmitter uptake by astrocytes.

A

Uptake is an important mechanism to inactivate the effects of an action potential. Astrocytes are able to uptake Glutamate (excitatory) and GABA (inhibitory). Astrocytes convert glutamate to glutamine by adding ammonia (using a by-product to make a product)

130
Q

What is glucose converted to by astrocytes to supply neurons with energy?

A

Lactic acid.

131
Q

Where do microglia arise? What are they?

A

Blood. Immune system cells. They phagocytose dead or damaged brain cells and kill invading cells.

132
Q

What is the composition of the ependyma?

A

The ependyma consists of ependymal cells derived from neuronal stem cells. These form a simple cuboidal epithelium. These cells have microvilli and cilia on their surface. The cilia help move the CSF around.

133
Q

Where are tanycytes found and what is their function?

A

They’re found on the in the third ventricle and on the floor of the fourth ventricle. They have processes running deep into the hypothalamus and are believed to transfer chemical signals from the CSF to the CNS

134
Q

What is the function of myelin?

A

To increase conduction velocity.

135
Q

What stain allows myelin to be seen under an electron microscope?

A

Osmium

136
Q

What technique can be used to see the multiple layers of myelin?

A

Freeze fracture

137
Q

What cells make myelin in the PNS?

A

Schwann Cells. They myelinate individual axons. They can completely ingulf the axon in an intimate association but may not myelinate it.

138
Q

What cells make myelin in the CNS?

A

Oligodendrocytes. These can myelinate multiple different axons or several parts of the same axon.

139
Q

Why is myelin layered?

A

Due to protein-lipid repeats.

140
Q

Myelin composition.

A

Water 40%
Lipid 70-85%
Protein 15-30%

141
Q

What are cerebrosides?

A

A group of glycosphingolipids important in the formation of myelin. Myelin develops in vacuoles.

142
Q

What 2 proteins are involved in CNS myelin?

A 
Myelin Basic protein (MBP)
Proteolipid protein (PLP)
143
Q

What protein is a major component of PNS myelin?

A

P0

144
Q

What does a mutation in proteolipid protein cause in mice?

A

Jimpy. These mice have motor disturbances due to synthesising little myelin. This occurs due to a servere loss in oligodendrocytes. The have problems in the motor coordination in their back legs.
Oligodendrocytes are producing PLP but it is toxic, thus killing off the oligodendrocytes.

145
Q

What happened to mice with proteolipid protein elimination?

A

Rumpshaker.

146
Q

What happens if you inject myelin basic protein into a host organism?

A

You can induce a condition called Experimental allergic encephalomyelitis (EAE). Uses to invastigate MS.

147
Q

How do shiver mice occur?

A

Due to a problem in the synthesis of myelin basic protein.

148
Q

What can be used as a marker for myelin in the lab?

A

Cyclic nucleotide phosphodiesterase (PDE)

149
Q

Name a syndrome caused by a disturbance in the P0 protein.

A

Charcot Marie Tooth Syndrome.

150
Q

Name a syndrome caused my CNS myelin degradation.

A

Multiple sclerosis.

151
Q

Name a syndrome caused by PNS myelin degredation

A

Guillian-Barre syndrome.

152
Q

What’s the difference between action potentials and graded potentials?

A

Action potentials are a fixed size (all or nothing) which are propagated over long the axon. Whereas graded potentials are variable size and are local signals so are NOT propagated across long distances.

153
Q

What is the Equilibrium potential?

A

The membrane potential that would be achieved in a neuron if the membrane was permeable to only that ion.

154
Q

What is the function of the Na/K ATPase complex in a neuron?

A

To maintain the resting potential by maintaining a large K concentration gradient across the neuronal membrane.

155
Q

What is an axodendritic synapse?

A

A synapse in contact with a dendrite

156
Q

What is an axosomatic synapse?

A

A synapse in contact with the cell body

157
Q

What is an axoaxonic synapse?

A

A synapse in contact with the axon

158
Q

What is a dendro-dendritic synapse?

A

A synapse between two dendrites (instead of an axon and a dendrite)

159
Q

Where are neurppeptides synthesised and stored in a synapse?

A

Synthesised in the soma and stored in secretory granules.

160
Q

By what process do vesicles fuse with the membrane and release their contents?

A

Exocytosis

161
Q

What 2 types of receptor are found on the post synaptic knob?

A

Ligand-gated ion channels (ionotropic)

G-protein coupled receptor (metabotropic)

162
Q

Name an agonist for nicotinic receptors?

A

Nicotine

163
Q

Name an antagonist for nicotinic receptors?

A

Curare

164
Q

Name an agonist for muscarinic receptors?

A

Muscarine

165
Q

Name an antagonist for muscarinic receptors?

A

Atropine.

166
Q

What enzyme catalyses the reaction of Acetyl coA + Choline?

A

Choline Acetyltransferase

167
Q

What enzyme catalyses the degredation of ACh to Acetic acid and choline?

A

Acetylcholinesterase.

168
Q

What are the three tunicas of the eye?

A

Tunica fibrosa
Tunica casculosa
Tunica interna

169
Q

What is the tunica fibrosa comprised of?

A

Sclera

Cornea

170
Q

What is the tunica vasculosa comprised of?

A

Choroid
Ciliary body
Iris

171
Q

What is the tunica interna comprised of?

A

Retina

Optic nerve

172
Q

What is the term used when the eye is at rest?

A

Emmetropia

173
Q

What happens if eye pressure becomes too high?

A

Glaucoma

174
Q

What happens when eye pressure becomes too low?

A

Cataracts

175
Q

How does Tapitum allow nocternal animals to see in the dark?

A

Acts as a mirror in the eye. it enhances the chance of protons entering the eye and stimulating photoreceptors.

176
Q

What pigment is used in rod cells?

A

Rhodopsin

177
Q

What pigment is used in cone cells?

A

Photopsin.

178
Q

Describe features of an ON bipolar cell.

A 
Hyperpolerised in the dark
Depolarised in central illumination
Metabotrophic glutamate receptors
Conductance increases in light
Light response leads to loss of inhibition by glutamate
179
Q

Describe features of an OFF bipolar cell.

A 
Depolerised in the dark
Hyperpolerised in central illumination
ionotrpoic glutamate receptors
conductance decreases in light
light response leads to loss of excitation by glutamate.
180
Q

Describe what happens when Rhodopsin is activated.

A

Light hits rhodopsin, activating it. Rhodopsin catalyses the transformation of Transducin GDP to Transducin GTP. This then stimulates the activation of PDE. PDE allows the hydrolysis of cGMP to GMP. GMP originally causes Na channels to close. this closure results in the concentration of Ca to decrease in the cytosol. As a result recoverin is released which generates the production of guanylate cyclase which converts GMP to cGMP. cGMP opens Na channels allowing action potentials to be generated.

181
Q

How many cone cells are there?

A

6-7 million

182
Q

Where are red and green cone cells located?

A

Fovea centralis

183
Q

Where are blue cone cells located?

A

Outside the fovea

184
Q

Name 4 papillae of the tongue.

A

Filiform
Foliate
Fungiform
Vallate

185
Q

Why is the Golgi Tendon Reflex a negative feeback circuit?

A

Because the activation of Ib afferents leads to the activation of inhibitory interneurones which inhibit Alpha motor neurones that innervate the same muscle.

186
Q

What carries mechanoreceptve and proprioceptive signals to the thalamus?

A

Medial leminscal tract

187
Q

What carries pain and temperature signals to the thalamus?

A

Spinothalamic tract.

188
Q

What is the visible portion of the ear called?

A

Pinna

189
Q

What is the entrance to the internal ear called?

A

Auditory Canal

190
Q

What is another name for the eardrum?

A

Tympanic membrane.

191
Q

What are the bones connected to the medial surface of the Tympanic membrane called?

A

Ossicles

192
Q

Where is the sensory information detected in the cornea transferred to?

A

Thalamus. More specifically, the Medial Geniculate Nucleus. The MGN then projects it to the Primary Auditory cortex in the temporal lobe.

193
Q

What are the three ossicles called?

A

Malleus (Hammer)
Incus (Anvil)
Stapes (Stirrup)

194
Q

What are the 3 fluid filled spaces in the Cornea called?

A

Scala vestibuli
Scala media
Scala tympani

195
Q

What membrane separates the Scala vestibuli from the Scala media?

A

Reissner’s membrane

196
Q

What membrane separates the Scala tympani from the Scala media?

A

Basilar membrane

197
Q

Where does the scala tympani become continuous with the scala vestibuli?

A

Helicotrema

198
Q

What is the fluid in the Scala vestibuli and Scala Tympani called?

A

Perilymph (Has low K and high Na)

199
Q

WHat is the fluid in the Scala media?

A

Endolymph (Has high K and low Na)

200
Q

Why does the knee jerk in the Patellar reflex?

A

The knee jerks due to a stretch (myotactic) reflex. The tap on the knee stretches the thigh extensor muscle and its associated tendon, as a result the jerk it set into motion to correct the change.

201
Q

What is the name of the sensory receptor that detects the muscle change in the knee jerk experiment?

A

The Muscle Spindle.

202
Q

What is reciprocal inhibition?

A

When one muscle in an antagonistic pair is forced to relax to accommodate for the contraction of the other muscle.

203
Q

What sensory fibers innervate muscle spindles?

A

Primary Afferent sensory fibres (Ia)

204
Q

What do Ia sensory fibers do in the knee jerk?

A

They provide feedback to the Alpha motor neurones on the amount of muscle stretch that is occuring.

205
Q

Name 3 components of the muscle spindle.

A

Alpha motor neurones
Gamma motor neurones
Ia Sensory neurones.

206
Q

What is the role of gamma motor neurones in the muscle spindle?

A

They stimulate the intrafusal muscle fibres to adjust the tension of the spindle as the extrafusal muscle fibres of the surrounding muscle contract (ensuring the muscle spindle is never in slack)

207
Q

What is proprioception?

A

The sense of positions of the body in relation to neighbouring parts of the body.

208
Q

How do GTOs act in a negative feedback loop?

A

When activated they activate inhibitory interneuons which in turn inhibit Alpha motor neurons in the same muscle.

209
Q

How do the medial leminiscal system pathways differ between upper and lower parts of the body?

A

1st order neurons in the upper body follow a lateral pathway and synapse with 2nd order neurones at the cuneate nucleus.
1st order neurons in the lower body follow a medial pathway and synapse with 2nd order neurones at the gracile nucleus.
These together are called the dorsal column nuclei.

210
Q

Where in the brain converts short term memory to long term memory?

A

Hippocampus

211
Q

Where in the brain processes multiple sensory inputs?

A

Amygdala

212
Q

Where in the brain processes procedural information?

A

Cerebellum

213
Q

How many layers does the hippocampus have?

A

3

214
Q

Who invented the EEG?

A

Hans Berger

215
Q

What is anabolism?

A

Breaking down macromolecules for energy storage

216
Q

What is catabolism?

A

Breaking down macromolecules for energy usage

217
Q

What did surgical cuts in both sides of a rat’s lateral hypothalamus cause?

A

Anorexia

218
Q

What did bilateral lesions of the venteromedial hypothalamus cause in rats?

A

Overeating and obesity.

219
Q

Where do high levels of leptin act? And what do the activated neurons contain? Where do these neurons send projections to?

A

On the arcuate nucleus of the hypothalamus. They contain neurotransmitters Alpha-MSH and CART. These send projections to the lower brainstem, spinal cord, paraventricular nucleus of the hypothalamus and the lateral hypothalamus.

220
Q

What does stimulation of the paraventricular nucleus of the hypothalamus do?

A

Stimulates the release of TSH and ACTH from the anterior pituitary gland.

221
Q

What do TSH and ACTH do?

A

Act on the thyroid and adrenal gland to increase basal metabolic rate.

222
Q

Name 2 anorectic peptides (appitite supressors)

A

Alpha-MSH and CART

223
Q

Where do low levels of leptin act? What do NT do they stimulate the release of? What are the effects?

A

Act on the arcuate nucleus of the hypothalamus. Stimulate the release of NPY and AgRP. These inhibit TSH and ACTH secretion, stimulate feeding behaviour and activatwe the parasympathetic NS.

224
Q

Name 2 orexigenic peptides

A

NPY and AgRP

Biomedical Science (8 decks)

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