Nervous And Endocrine Systems

Question 1

Homeostasis feedback loop

Answer 1

Deviation -> sensor -> integrator -> effector -> compensatory response -> homeostasis

Question 2

ANS homeostasis feedback loop

Answer 2

Physiological/environmental change -> sensory neurons (sensory information) -> CNS (hypothalamus & brainstem, activation of ANS) -> muscle contraction or relaxation, activation or inhibition of secretion from glands -> physiological response

Question 3

What are the advantages of a 2 neuron train?

Answer 3

• one preganglionic neuron can synapse into many postganglionic neurons
• one preganglionic neuron can synapse into both inhibitory and excitatory neurons
• information from sensory axons can have a direct rapid reflex effect on output

Question 4

What are the divisions of the ANS?

Answer 4

• sympathetic
• parasympathetic
• enteric

Question 5

Where do sympathetic nerves originate from?

Answer 5

Thoracic and lumbar regions

Question 6

Where do parasympathetic nerves originate from?

Answer 6

Brain and sacral region

Question 7

What are the relative lengths of preganglionic neurons?

Answer 7

Sympathetic: short
Parasympathetic: long

Question 8

What effect does the sympathetic NS have on the heart?

Answer 8

• increased contractility on the presence of noradrenaline

Question 9

What effect does the sympathetic NS have on veins and arteries?

Answer 9

• construction of arteriole and venous smooth muscle

- increased blood pressure

Question 10

What effect does the sympathetic NS have on the pupil?

Answer 10

• pupils dilate to let more light in and adjust for far vision

Question 11

What effect does the sympathetic NS have on the airway smooth muscle?

Answer 11

Relaxation of airway muscle

Question 12

What effect does the sympathetic NS have on the sweat glands?

Answer 12

Increased sweating

Question 13

What is a chromaffin cell?

Answer 13

A modified post ganglion is neuron

Question 14

Which hormones does the chromaffin cell secrete?

Answer 14

Adrenaline: 80%
Noradrenaline: 20%

Question 15

Which organ does not receive both parasympathetic and sympathetic innervation?

Answer 15

Blood vessels - generally only receive sympathetic nerve fibres

Question 16

What is an example of where sympathetic and parasympathetic do not have antagonistic effects?

Answer 16

Salivary glands: both will stimulate the secretion of saliva

Question 17

What happens in the cold water immersion?

Answer 17

1. Dive reflex: facial immersion stimulates mechano and thermoreceptors and activates the parasympathetic NS, results in bradycardia which is further increased by breathholding
2. The cold shock response: immersion stimulates cutaneous cold receptors on the rest of the body which activates the sympathetic ANS resulting in tachycardia

Question 18

What are the 2 reflexes in a cold water immersion?

Answer 18

Dive reflex

Cold shock response

Question 19

Which neurotransmitter and receptor are involved in all preganglionic to postganglionic synapses?

Answer 19

ACh, cholinergic nicotinismo receptors

Question 20

How are circulating catecholamines broken down in the liver?

Answer 20

Inactivated by catechol-o-methyltransferase

Question 21

How is NA broken down?

Answer 21

Rapidly re-sequestered by the sympathetic nerves

May be the broken down by monoamine oxidase

Question 22

How is acetylcholine broken down?

Answer 22

Extracellular acetylcholinesterases

Question 23

What are the noradrenaline receptors?

Answer 23

Alpha 1 & 2, beta 1 & 2

Question 24

Muscarinic acetylcholine receptors

Answer 24

• named after the agonist muscarine
• found on target cell innervates by the parasympathetic branch
• blocked by atropine

Question 25

Nicotinic acetylcholine receptors

Answer 25

- named after agonist nicotine | - are found on post ganglionic target cells and skeletal muscle cells (somatic’

Question 26

Alpha 1 receptors

Answer 26

- vein/arteriole smooth muscle - contraction - stimulatory - higher for NA

Question 27

Alpha 2 receptors

Answer 27

- endocrine pancreas - inhibits insulin release - inhibitory - higher for NA

Question 28

Beta 1 receptors

Answer 28

- heart - increases rate and force - stimulatory - similar affinity

Question 29

Beta 2 receptors

Answer 29

- airway smooth muscle - relaxation - inhibitory - much higher for ADR

Question 30

What are the three types of hormones?

Answer 30

1. Peptide and protein 2. Steroid 3. Hormones derived from tyrosine

Question 31

Which hormones are derived from tyrosine?

Answer 31

Catecholamines, thyroid hormone

Question 32

What is the posterior pituitary also known as?

Answer 32

Neurophypophysis

Question 33

Which hormones are secreted by the posterior pituitary?

Answer 33

- oxytocin | - ADH

Question 34

Oxytocin hormone sensory stimuli

Answer 34

Stretch receptors

Question 35

What is the target tissue of oxytocin?

Answer 35

Breast myoendothelial cells

Question 36

What is the anterior pituitary also known as?

Answer 36

Adenohypophysis

Question 37

What are the hypophysiotrophic hormones?

Answer 37

- GnRH - GHRH - SS - TRH - DA - CRH

Question 38

What is the result of the cold water immersion?

Answer 38

- results in 2 opposing influences acting on the heart simultaneously - arrhythmia

Question 39

What does growth hormone releasing hormone do?

Answer 39

Stimulates growth hormone secretion

Question 40

What does corticotrophin releasing hormone do?

Answer 40

Stimulates adrenocorticotrophic hormone secretion

Question 41

What does thyrotropin releasing hormone do?

Answer 41

Stimulates the secretion of prolactin and thyroid stimulating hormone

Question 42

What does dopamine do?

Answer 42

Inhibits the release of prolactin

Question 43

What does somatostatin do?

Answer 43

Inhibits the release of TSH and GH

Question 44

What does gonadotrophin releasing hormone do?

Answer 44

Stimulates the secretion of FSH and LH

Question 45

Where is cortisol secreted from?

Answer 45

Zona fasciculata of the adrenal cortex

Question 46

How much cortisol is secreted per day?

Answer 46

10mg

Question 47

When are minimum levels of cortisol found?

Answer 47

Midnight

Question 48

When are maximum levels of cortisol found?

Answer 48

Early morning

Question 49

What is the main effect of cortisol?

Answer 49

Increased serum glucose

Question 50

How does cortisol increase serum glucose?

Answer 50

- increased gluconeogenesis in the liver - decreases peripheral glucose utilisation (antagonises insulin, but muscle, brain and heart gave insulin-independent glucose uptake)

Question 51

What are other effects of cortisol during stress?

Answer 51

- activates lypolysis - suppresses reproductive, immune and digestive function via the sympathetic nervous system - promotes analgesia -> don’t feel as much pain - increases vascular response to catecholamines

Question 52

What is Cushing’s syndrome?

Answer 52

Overproduction of cortisol

Question 53

What are the potential causes of Cushing’s syndrome?

Answer 53

1. Oversecretion of CRH by hypothalamic tumor 2. Over secretion of ACTH by ATCH secreting pituitary tumor 3. Negative feedback problems: CRH/ACTH secretion insensitive to raised cortisol levels

Question 54

What are the symptoms of Cushing’s disease?

Answer 54

- diabetes mellitus - central obesity - thinning of skin and bruising - muscle wasting

Question 55

What is the treatment for Cushing’s disease?

Answer 55

Removal of the usually benign tumor

Question 56

How does cortisol increase gluconeogenesis?

Answer 56

- inhibits amino acid uptake everywhere apart from the liver | - promotes the breakdown of muscle to amino acids

Question 57

What are the levels of the adrenal glands and what do they secrete?

Answer 57

Zona fasciculata: adrenal cortex - secretes cortisol | Andrenal medulla: chromaffin cells - catecholamines

Question 58

What are some stresses that increase the levels cortisol?

Answer 58

Hypoglycaemia, fever, trauma, haemorrhage