Physiology 2

Question 1

What does the hypothalamus release?

Answer 1

Neurohormones. Because its brain tissue releasing a chemical into the blood to work on a distal site.

Question 2

What is the role of the hypothalamus?

Answer 2

It is the integration centre for the endocrine system. It holds nerves which project down into the posterior pituitary.

Question 3

How is the posterior pituitary connected to the hypothalamus?

Answer 3

Via the infundibulum.

It is a continuation of the nerves from the hypothalamus. It contains nerve terminals and axons.

Question 4

How is the anterior pituitary connected to the hypothalamus?

Answer 4

Via the capillary portal system.
It wraps itself round the posterior pituitary.
IT is connected via neurohormones.

Question 5

What are the differences between the anterior and posterior pituitary?

Answer 5

Anterior is epithelial in origin, posterior is nervous tissue in origin.
Anterior isn’t directly attached to the hypothalamus and the posterior is.
Anterior produces its own hormones and posterior doesn’t.

Question 6

Where is the pituitary gland located?

Answer 6

In the hypophyseal fossa of the sphenoid bone. Below the hypothalamus and optic chiasm.

Question 7

what is the tiny middle lobe of the pituitary called?

Answer 7

The pars intermedia. It secreted melanocyte releasing hormone.

Question 8

What are tropic hormones?

Answer 8

These control the release of another hormone.

Question 9

What are non-tropic hormones?

Answer 9

These don’t control the release of another hormone. They directly stimulate a target cell.

Question 10

What are the non-tropic neurohormones released via the posterior pituitary?

Answer 10

Vasopressin - maintains water balance.

Oxytocin - stimulates uterine contraction and parturition, aids expression of milk in the lactating breast.

Question 11

What do the hypothalamic tropic hormones do?

Answer 11

They stimulate or inhibit the release of hormones from the anterior pituitary.

Question 12

How many hypothalamic releasing hormones?

Answer 12

5

Question 13

How many hypothalamic inhibiting hormones?

Answer 13

2

Question 14

How many hormones are released from the anterior pituitary?

Answer 14

6 - 5 of these are tropic hormones.

They are all peptides.

Question 15

What is a trophic hormone?

Answer 15

These have an effect on growth, either directly or indirectly.

Question 16

What controls negative feedback for the anterior pituitary?

Answer 16

Usually in response to the hormone.

The hypothalamus, anterior pituitary and target endocrine cell. This is long-loop feedback and short-loop feedback.

Question 17

How is the parathyroid feedback different?

Answer 17

its not in response to the hormone, it is in response to the physiological response (the raised calcium levels in plasma).

Question 18

what is hypo secretion?

Answer 18

when too little hormone is secreted.

Question 19

What is hyper secretion?

Answer 19

When too much hormone is secreted.

Question 20

What are endocrine disorders caused by?

Answer 20

Primary, secondary or tertiary disorders.

Question 21

What are primary disorders?

Answer 21

a defect in the cells that secrete the hormone (end organ) - common.

Question 22

What are secondary disorders?

Answer 22

when there is too much or too little tropic hormone in the pituitary - fairly common.

Question 23

What are tertiary disorders?

Answer 23

When there is hypothalamic defects, ie - not enough releasing hormone secreted - Rare.

Question 24

What is hypo responsiveness?

Answer 24

Not enough response from the body to the hormone. Receptors might be under expressed, antagonistic effects from other hormones. Disordered post-receptor failure.

Question 25

What is hyper responsiveness?

Answer 25

Too much response. Could be due to permissive effect (one hormone enhancing the activity of another).

Question 26

What is a permissive effect?

Answer 26

When one hormone alters the activity of another.

For example, thyroid hormone increases adrenaline mediated lipolysis.

Question 27

Why is thyroid hormone needed?

Answer 27

For growth hormone to act normally.

Question 28

What happens with too little growth hormone?

Answer 28

As long as the individual has enough thyroid hormone, they will be small but well proportioned.

Question 29

What happens with too little thyroid hormone?

Answer 29

The individual will be small and disproportionate. Thyroid hormone is needed in order for growth hormone to act normally (without it bones don’t elongate properly).

Question 30

What can cause hyper-responsiveness?

Answer 30

Prolonged exposure to low concentrations of hormone in the plasma. = increase in receptors.

Question 31

What causes hypo-responsiveness?

Answer 31

Prolonged exposure to high concentrations of plasma hormone. = down regulation in receptor expression.

Question 32

What is an example of an antagonistic response?

Answer 32

Growth hormone impairs glucose uptake in response to insulin in muscle and adipose tissue - by decreasing insulin receptors on them. This allows more glucose to go to other parts of the body to grow.

Question 33

What are the hypothalamus posterior pituitary hormones?

Answer 33

Vasopressin (ADH) and oxytocin.

Question 34

What are the hypothalamus hormones acting on the anterior pituitary?

Answer 34

5 releasing:
Growth hormone releasing hormone
Prolactin releasing hormone
thyrotropin releasing hormone
Gonadotropin releasing hormone
corticotropin releasing hormone 

2 inhibitory:
Growth hormone inhibitory hormone
dopamine (prolactin inhibitory hormone)

Question 35

What are the anterior pituitary hormones?

Answer 35

5 tropic:
Growth hormone
Luteinising hormone
Follicle stimulating hormone
thyroid stimulating hormone
adrenocorticotropic hormone

1 non-tropic:
prolactin