Endocrine System Flashcards

1
Q

Describe what a myelinated neuron looks like

A

Axon in the middle surrounded by myelin sheath which has been secreted by Schwann cell sitting around the outside

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2
Q

Describe what a non-myelinated neuron looks like

A

Multiple axons sitting inside a Schwann cell

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3
Q

Describe how a nerve impulse is transmitted

A

Nerve impulse generated
Voltage causes membrane structure change so voltage gated calcium channels open allowing calcium to flow freely from the presynaptic neuron into the synaptic cleft
This sets up a gradient allowing neurotransmitter containing vesicles to fuse with the presynaptic membrane and release the neurotransmitter into the synaptic cleft
Sodium channels open allowing sodium to flow into the postsynaptic neuron causing ligand gated channels to open
Sodium flows from the synaptic cleft into the postsynaptic neuron, having transmitted the nerve impulse

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4
Q

Symptoms of the alarm response

A
Increased heart rate
Increased sweating
Pupil dilation
Decreased salivation
Peripheral vasoconstriction
Bronchi dilation
Increased blood sugar
Increased blood pressure
Decreased digestion
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5
Q

Symptoms of the relaxation response

A
Decreased heart rate
Pupil contraction
Peripheral vasodilation
Bronchi constriction
Increased digestion
Increased salivation
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6
Q

Sympathetic division

A

Associated with
Exercise
Emotion
Excitement

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7
Q

Parasympathetic division

A

Associated with
Rest
Relaxation
Repletion

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8
Q

Autonomic nervous system properties

A

Mainly interoreceptors
Involuntary from limbic system, hypthothalamus, brain stem and spinal cord
Two-neuron pathway
Acetylecholine
Norepinephrine (postganglionic sympathetic fibres to areas other than sweat glands)
Smooth muscle, cardiac muscle, glands

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9
Q

Somatic nervous system properties

A
Special sense and somatic sense
Voluntary from cerebral cortex
One-neuron pathway
Acetylcholine
Skeletal muscle
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10
Q

Describe the sympathetic division innervation to effector tissues other than sweat glands

A

ACh travels along a cholinergic sympathetic preganglionic neuron
ACh released into autonomic ganglion where it is picked up by nicotinic receptors
ACh travels along adrenergic sympathetic poatganglionic neuron
NE released near effector cell where it is picked up by adrenergic receptors

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11
Q

Describe the sympathetic division innervation to sweat glands

A

ACh travels along a cholinergic sympathetic preganglionic neuron
ACh released into autonomic ganglion where it is picked up by nicotinic receptors
ACh travels along cholinergic sympathetic poatganglionic neuron
ACh released near sweat gland cell where it is picked up by muscarinic receptors

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12
Q

Describe the parasympathetic division innervation

A

ACh travels along a cholinergic sympathetic preganglionic neuron
ACh released into autonomic ganglion where it is picked up by nicotinic receptors
ACh travels along cholinergic sympathetic poatganglionic neuron
ACh released near effector cell where it is picked up by muscarinic receptors

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13
Q

Hypothalamus

A

Controls internal organs via autonomic nervous system and pituitary gland
Regulates behavioural patterns, circadian rhythms and body temperature
Regulates eating and drinking behaviour

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14
Q

HPA axis

A

Hypothalamus
Pituitary
Adrenal glands

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15
Q

Paracrine hormone

A

Released by paracrine cell to be used by a nearby cell

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16
Q

Autocrine hormone

A

Released by autocrine cell to be used by the original cell

17
Q

Describe control of hormone release

A
Synthesis, storage and release of hormone into blood by hormone producing cell
Travels through the bloodstream to target cell with receptors for specific hormone to achieve desired response
Hormone disposal by breakdown or excretion
Feedback signal (usually negative) acts on original hormone producing cell to stop (or continue) production
18
Q

Lipid soluble hormone action

A

Hormone cannot move through blood because it isn’t water soluble so it binds to a carrier protein to carry it through
Hormone dissociates from carrier protein and diffuses into cell through lipid membrane
Hormone binds intracellular receptor activating a receptor complex and altering gene expression
Newly formed mRNA directs synthesis of specific proteins on ribosomes
New protein alters cell activity

19
Q

Water soluble hormone action

A

Hormone can move through blood alone
Binds to receptor on cell surface because it can’t diffuse through lipid membrane
G protein is activated which in turn activates adenyl cyclase
Adenyl cyclase is cleaved by ATP to produce cAMP which acts on protein kinases
Phosphorylation cascade occurs
Phosphorylated enzymes catalyse reactions that produce physiological response

20
Q

Number of hormones synthesised by hypothalamus

A

9

21
Q

Number of hormones synthesised by pituitary

A

7

22
Q

Describe hypothalamic control of the pituitary gland

A

Hypothalamic neurosecretory cell releases hormone or hormone precursor into the top of the pituitary where they travel through hypophyseal portal veins to the secondary plexus and then to pituitary target cells

23
Q

Describe how the alarm response is enhanced

A

Sympathetic preganglionic neuron terminates in the adrenal medulla and stimulates (via ACh) epinerphrine and NE release into the bloodstream which enhances and sustains the alarm response

24
Q

Hormones from the adrenal medulla

A

Epinephrine and NE

25
Q

Hormones from the adrenal cortex

A

Mineralo-corticoids e.g. aldosterone

Glucocorticoids e.g. cortisol

26
Q

Describe how mineralo-corticoids work

A

Stimulated by increased potassium and angiotensin II which increases sodium and water levels and decreases blood potassium levels
This leads to increased blood volume and increased blood pressure

27
Q

Describe how cortisol work

A

Stimulated by ACTH which is released from the anterior pituitary by CRH from hypothalamus
Causes resistance reaction to stress, dampens inflammation and depresses immune responses
Cortisol then negatively feeds back on CRH

28
Q

7 properties of the resistance reaction (actions of cortisol)

A
Protein breakdown
Gluconogenesis
Lipolysis
Resistance to stres
Vasoconstriction
Anti-inflammatory
Immune depression
29
Q

Summarise the stress response (alarm + resistance reaction)

A

Stressor stimulates sympathetic nerves to act on adrenal medulla to secrete NE, immediately acting on visceral effectors causing the alarm response
At the same time but slower, stressor stimulates hypothalamus to secrete CRH into primary hypophyseal plexus then portal vein to secondary plexus to anterior pituitary
Anterior pituitary releases ACTH into bloodstream which acts on the adrenal cortex to release cortisol into the bloodstream which causes the resistance reaction
Once the stressor is removed, high levels of cortisol in the blood inhibits ACTH and CRH secretion

30
Q

3 links between the neuroendocrine and immune systems

A

Autonomic nerves
Hormones
Cytokines

31
Q

Stress cardiomyopathy syndrome

A

Overactivation of the stress response

32
Q

Habitually hostile people

A

Long term sympathetic activation
Heart working harder, capillaries constantly constricted
Increased risk of cardiac infarction