The Nervous System

Question 1

What response do nerves of the sympathetic nervous system exhibit?

Answer 1

The ‘fight or flight’ response

Question 2

Is the autonomic nervous system voluntary or involuntary? What can it be further split into?

Answer 2

The autonomic nervous system is involuntary - it can be further split into the sympathetic and parasympathetic nervous system

Question 3

What movement does the somatic nervous system control? What neurotransmitter is used in this system?

Answer 3

The somatic nervous system controls voluntary movement, via acetylcholine neurotransmission

Question 4

What neurotransmitter is used by the sympathetic nervous system?

Answer 4

Noradrenalin

Question 5

Sympathetic nerve fibres innervated all vessels except what?

Answer 5

Capillaries and precapillary sphincters

Question 6

How does noradrenalin from the sympathetic nervous system act on vessels in the skin?

Answer 6

It causes vasoconstriction, preventing blood loss to open wounds

Question 7

What neurotransmitter used in the parasympathetic nervous system?

Answer 7

Acetylcholine

Question 8

What 3 places in particular does the sympathetic nervous system promote blood flow?

Answer 8

The heart
The brain
Skeletal muscle

Question 9

What is endocrine communication?

Answer 9

Secretion of hormones directly into the bloodstream, as opposed to a duct

Question 10

Name the 9 major endocrine glands.

Answer 10

Pancreas
Thymus
Pineal glands
Gonads
Adrenal glands
Hypothalamus
Pituitary gland
Thyroid gland
Parathyroid gland

Question 11

What Greek word does the word ‘hormone’ come from?

Answer 11

To excite or arouse

Question 12

What 2 organs are considered the ‘conductors’ of the endocrine system?

Answer 12

The hypothalamus and the pituitary gland

Question 13

What is the role of the thymus?

Answer 13

It is involved in the maturation of bone marrow-derived stem cells into immunocompetent T lymphocytes, via production of thymosin (which promotes T cell maturation) - this process is know as thymic cell education

Question 14

What is a portal system? Which 2 places is this type of system found in the human body?

Answer 14

2 capillary systems in series - these are found in:

• hepatic portal system
• hypothalamo-hypophyseal system

Question 15

What is neurocine communication? What 3 organs use this type of signalling?

Answer 15

Neurocrine communication involves stimulation by a neuron to release molecules into the bloodstream - 3 organs that use this are:

• anterior pituitary
• posterior pituitary
• adrenal medulla

Question 16

State how the sympathetic nerves affect different organs.

Answer 16

Eyes - pupils dilate
Salivary glands - inhibits production of saliva
Lungs - bronchodilation 
Heart - increases heart beat
Stomach - inhibits digestion
Kidneys - stimulates adrenaline and noradrenaline release
Liver - promotes glucose release 
Bladder - relaxes bladder

Question 17

How does the sympathetic nervous system affect veins leading to the heart?

Answer 17

It causes venoconstriction, which increases cardiac return

Question 18

Describe the synthesis, storage, transport, and location of receptor of peptide hormones.

Answer 18

Peptide hormones are sysnthesised beforehand, and are stored in secretory vesicles - they are transported dissolved in plasma, and bind their receptors on the surface of the cell membrane

Question 19

What organ serves as the point where the nervous system and the endocrine system communicate?

Answer 19

The hypothalamus

Question 20

State how the parasympathetic nerves affect various organs.

Answer 20

Eyes - pupils constrict
Salivary glands - stimulates saliva production
Lungs - stimulates bronchoconstriction 
Heart - decreases heart beat
Stomach - stimulates digestion
Kidneys - inhibits adrenaline and noradrenaline secretion
Liver - stimulates bile secretion 
Bladder - contracts bladder

Question 21

Describe the mechanism of the hypothalamic-pituitary-thyroid axis. What is the action of its feedback loop?

Answer 21

The hypothalamus produces TRH (thyrotropin-releasing hormone) which travels through the hypothalamic-hypophyseal portal system to the pituitary gland where it stimulates TSH (thyroid-stimulating hormone) secretion into the bloodstream - this reaches the thyroid gland and stimulates the release of T3 & T4, which stimulate metabolism - these then act in a negative feedback loop

Question 22

Describe the synthesis, storage, transport, and location of receptor of steroid hormones.

Answer 22

Steroid hormones are synthesised on demand and as such have no need to be stored - they are transported in the blood bound to carrier-proteins, and act mainly on receptors at the nuclear envelope (although some act at the plasma membrane and in the cytoplasm)

Question 23

There are 2 tyrosine-derivative hormones - what are they?

Answer 23

Catecholamines and thyroid hormones

Question 24

How may the pituitary gland be divided?

Answer 24

Into 2 lobes - the posterior pituitary and the anterior pituitary

Question 25

Which part of the hypothalamic-pituitary-thyroid axis is an example of neurocrine secretion?

Answer 25

The secretion of TRH and its subsequent transport through the hypothalamo-hypophyseal portal system

Question 26

What makes the pineal gland visible on an X-Ray scan?

Answer 26

It becomes calcified in early adulthood

Question 27

Where are the adrenal glands located? What response are they involved with?

Answer 27

The adrenal glands are located superior to the kidneys, and are involved in the stress response

Question 28

Where are the principal effectors of the stress response localised?

Answer 28

The hypothalamus The anterior pituitary The adrenal glands

Question 29

What 2 structures make up the adrenal gland?

Answer 29

The cortex and the medulla

Question 30

List 2 adrenal cortical steroids, and an example of each. Where are they secreted from?

Answer 30

Glucocorticoid (cortisol) Mineralocorticoid (aldosterone) They are secreted from the cortex of the adrenal glands

Question 31

What type of feedback exists in the hypothalamo-pituitary-adrenal axis? What hormone produces this feedback?

Answer 31

Negative feedback via cortisol

Question 32

In the hypothalamo-pituitary-adrenal axis, what hormone is involved in endocrine secretion across the hypothalamo-hypophyseal portal system? What molecule does this stimulate?

Answer 32

Corticotrophin-releasing hormone travels through the hypothalamo-hypophyseal portal system from the hypothalamus, and stimulates adrenocorticotropic hormone at the anterior pituitary gland

Question 33

Describe how the tyrosine derivatives (thyroid hormone and catecholamines) are synthesised, stored, transported, and the location of their receptor. How do they differ?

Answer 33

Catecholamines are synthesised beforehand and stored in secretory vesicles - they are transported diffused in the plasma, and bind receptors on the cell membrane Thyroid hormones are sysnthesised beforehand, and their precursor is stored in secretory vesicles - they travel in the bloodstream bound to carrier proteins, and their receptors are located at the nuclear envelope

Question 34

Once bound to their homologous receptor, which 2 hormones mediate their effects via secondary messenger systems?

Answer 34

Peptide hormones and catecholamines

Question 35

Where are chromaffin cells located? What substances do they release, and what type of innervation results in this release?

Answer 35

Chromaffin cells are located in the medulla of adrenal glands (the adrenal medulla) and secrete adrenaline and noradrenaline upon stimulation by the sympathetic nervous system

Question 36

What effect does receptor-ligand binding of steroid hormones and thyroid hormones produce? Where therefore do they bind their receptor?

Answer 36

Activation of genes for transcription and translation - they bind their receptor at the nuclear membrane

Question 37

List 4 effects of adrenaline/noradrenaline.

Answer 37

Increased heart rate Increased breathing rate Increase blood glucose (more glycogen broke down to glucose) Increased metabolic rate

Question 38

What primary hormone does the pineal gland secrete? How does this hormone act?

Answer 38

The pineal gland secretes melatonin - this controls cardiac rhythm

Question 39

Name 2 hormones that are secreted by the posterior pituitary.

Answer 39

Oxytocin | ADH

Question 40

What does melatonin inhibit? Conversely, what inhibits melatonin release?

Answer 40

Melatonin inhibits the release of gonadotrophins (LH & FSH) - light exposure inhibits melatonin secretion

Question 41

Which plane does the pineal gland sit on?

Answer 41

The midline

Question 42

What class of hormone does the adrenal cortex secrete?

Answer 42

Steroid hormones