Chapter 7/23 - Endocrine System

Front 1

How are hormones able to travel from their cells to their targets?

Back 1

They are secreted by endocrine cells, cytokines, glands or neurons to travel by blood to their target.

Front 2

Why can the response of a target to one hormone differ?

Back 2

Response depends on the target's receptor and the transduction pathway used.

Front 3

Hormone X has a rapid target response. Why is this possible? What would be the opposite effect?

Back 3

This would be a peptide hormone which alters proteins already made, leading to a quick response.

Front 4

Hormone A effects brain tissue and initiates gluconeogenesis. How is this possible?

Back 4

This is a steroid hormone which targets gene expression and is lipophilic so it passes the BBB.

Front 5

Why are hormones, other than thyroid hormone, secreted in a interval like manner?

Back 5

They are not constantly needed, so they only made when the need is there. Thyroid hormone aid metabolism, which is a constant process.

Front 6

Define the equilibrium regarding hormones.

Back 6

Lipophilic hormones bound to proteins and free hormones are in equilibrium.

Front 7

Compare and contrast the three classes of hormones in these situations:
synthesis and storage
release
transport
half-life
receptor location
target response

Do you see any similarities?

Back 7

Refer to Table 7.1of text.

Front 8

How does the protein hormone become its active form?

Back 8

1) The precursor is called a preprohormone which has the signal sequence which takes it to the ER.
2) After modifications at the ER/Golgi, it is a smaller prohormone (still inactive).
3) Post-translational modification (remove fragments to activate it)
4) Active hormone which binds to the membrane receptor.

Front 9

How is the steroids long half life maintained?

Back 9

By binding to proteins, their effect is extended but they are prevented from entering cells because the proteins are lipphobic.

Front 10

How do precursors create a family of hormones?

Back 10

The resulting hormones have a similar structure that allow for a similar effect but the difference in structure, like difference in rings, inhibits an identical effect.
Ex. cholesterol making steroids like cortisol, estrogen, and aldosterone.

Front 11

Why is tyrosine the precursor for a specific class of hormones?

Back 11

It is a amino acid that creates more amines, like melatonin, catecholamines and thyroid.

Front 12

What mechanism ensures that the pathway of hormones is maintained?

Back 12

Negative feedback - feeds from both gland to hypothalamus and pituitary glad to hypothalamus so only the right amount of hormone is secreted.

Front 13

There is a hyper secretion of cortisol at the adrenal cortex. Describe that pathway. What can this be caused by?

Back 13

Corticoptropic releasing H and adrenocorticotropic H would be low and may atrophy. This can be caused by cancers or exogenous source of steroids.

Front 14

How are the three integrating centers of the endocrine control pathway maintained?

Back 14

By the hypothalamic hypophyseal portal system (blood system)

Front 15

Using the growth hormone pathway example, describe the effects of a primary/secondary/tertiary hypo/hyper secretion.

Back 15

See page 4 of endocrine system.

Front 16

How can hormones interact with one another?

Back 16

1) synergism - magnify the effect by adding hormones together.
2) permissiveness - need 2nd hormone for full effect.
3) antagonistic - oppose the other hormones effect either physically or functionally. `

Front 17

Why is there negative feedback in only one type of endocrine pathologies?

Back 17

With hyposecretion and the lack of - feedback, the hypothalamus does not know that the gland is secreting less hormone so it does not receive the signal to make more.
With hypersecretion, there is - feedback but the tumor/exogenous steroid keeps making more gland hormone, even if the trophic hormone concentrations are less.

Front 18

How does the body work against hypoglycemia?

Back 18

Cortisol is released to promote gluconeogenesis and lipolysis to prevent glucose levels from becoming too low.

Front 19

Where is cortisol released from? What else is released from there?

Back 19

The zona fasciulada of the adrenal cortex. Aldosterone (zona glomerulosa) and androgens (zona reticularis) are also released.

Front 20

Why could cortisol be used as a therapeutic drug?

Back 20

It prevents the inflammatory body response and also suppresses the immune system to prevent rejection.

Front 21

Anna has very little energy and is unable to deal with life's stresses. What is the pathology?

Back 21

Addison's disease which is caused by hyposecretion of the cortisol hormones.

Front 22

How can hypercorticolism be caused?

Back 22

Exogenous drugs causing tropic atrophy or tumours secreting more tropic hormones.

Front 23

How is skin pigmentation and hypersecretion of ACTH caused?

Back 23

POMC makes ACTH, which also stimulate melanocytes which act on melanin to colour your skin. High ACTH = high melanocyte stimulation = more pigmentation.

Front 24

How can you classify thyroid hormone?

Back 24

An amine that acts like a steroid because it binds to plasma proteins to extend their half life.

Front 25

How is active thyroid hormone made?

Back 25

Hypothalamus - thyrotropic releasing hormone

Ant Pit - thyroid stimulating hormone

Thyroid gland - t4 released

Diodinase - remove iodine to make active t3

Front 26

Iodine deficiency can cause what pathology?

Back 26

Goiters because there is not enough iodine to make active t3 but the gland is constantly stimulated because the hypothalamus knows that there is not enough T3 but it can't be made. Over stimulation causes the enlargement.

Front 27

How do hypersecretion pathologies compare?

Back 27

They can have tumours or abnormal cells or exogenous sources of the gland hormone which causes hypersecretion.

Front 28

What is the general principle of hypo____ pathologies?

Back 28

There is a lack of negative feedback that prevents the hypo/ant pit from knowing there is a deficient amount of gland hormone.

Front 29

Compare and contrast hypo/hyperthyroidism is regards to the body systems they effect.

Back 29

Consider pulmonary, cardiovascular, muscular and nervous.

Front 30

Why is growth hormone required throughout life?

Back 30

To maintain development throughout life.

Front 31

Other than the growth hormone releasing hormone, what other hormones can be triggered?

Back 31

Stress and circadian rhythm can also activate somatostatin, an inhibitory hormone.

Front 32

Give an example of an anabolic hormone. Why is this the right answer?

Back 32

Growth hormone which promotes protein synthesis.

Front 33

What is the action of thyroid hormone?

Back 33

Metabolism, increased o2 consumption and protein catabolism.

Front 34

Simon has a long jaw and large hands and feet. What is the pathology? Why?

Back 34

Too much GH which causes overdevelopment of these features.

Front 35

How do soft tissue and bone growth needs differ in order to grow?

Back 35

Tissue growth needs hormones and paracrines to provide energy and protein synthesis.

Bone growth needs calcium.

Front 36

Sandy has been experiencing weak bones that break easily. What is the pathology?

Back 36

With more osteoclasts, the bones are absorbing faster than they are depositing (osteoblasts), causing the bone loss and fragility.

Front 37

Differentiate between hypocalcemia and hypercalcemia in regards to the nervous system.

Back 37

Hypocalcemia = less calcium = more Na into the cell = more depolarizations.

Hypercalcemia = more calcium = less Na into the cell = less depolarizations.

Front 38

How is calcium an important signal molecule?

Back 38

Once it reaches its target, the molecule and initiate contraction and vesicle exocytosis.

Front 39

Where can calcium be found?

Back 39

In the extracellular matix, fluid, and intracellular.

Front 40

Classify the three hormones that control calcium balance with the equation: total body calcium = intake - output

Back 40

Parathyroid hormone - increases intake by raising plasma Ca2+ from the bone, kidneys and intestines.

Calcitrol - increases intake by raising Ca2+ from the bone and re absorption in the kidney.

Calcitonin - increase output by moving Ca out of the body (kidney) and plasma (back to bone)

Front 41

How does phosphate homeostasis parallel calcium?

Back 41

Both are stores in the same places in the body (extracellular matrix/fluid, intracellular) and are deposited/reabsorbed in the same places (bones and kidneys).

Front 42

How can exercise prevent osteoporosis?

Back 42

Aerobic activities can increase bone mass which delays the process.