1 - Enodcrine System

Question 1

What are the 4 types of chemical messengers

Answer 1

1) Autocrine
2) Paracrine
3) Neurotransmitter
4) Endocrine

Question 2

What do Autocrines do?

Answer 2

effect the same cell, e.g. prostaglandin

Question 3

What does prostaglandin do?

Answer 3

They control processes such as inflammation, blood flow, the formation of blood clots and the induction of labour.

Question 4

What do pancreatic messengers do?

Answer 4

effect local cells. e.g. somatin

Question 5

What do hormones do?

Answer 5

Produced by endocrine system + travel to circulatory system

Question 6

Define hormones

Answer 6

secreted via endocrine glands, travelling via the blood to target tissues.

Question 7

Characteristics of hormones

Answer 7

1) stability: half life, water soluble (protein, epinephrine and norepinephrine)
2) Communication (with target cells)
3) Distribution (dissolve in blood plasma unbound. Unbound = distribute greatly OR Bound = distribute less (more concentrated, attaching to lipids)

Question 8

3 Patterns of hormone secreition

Answer 8

1) Chronic: stable concerntration
2) Acute: rapid increase due to stimulus
3) Episodic: increases and decreases at a constant rate

Question 9

Stimulatory Influences on hormone secretion + examples

Answer 9

1) Humoral
2) Neural
3) Hormonal

Question 10

Describe Humoral influences

Answer 10

Humoral: action of a substance which isn’t a hormone or endocrine gland.

Eg. Parathyroid Hormone. Calcium levels too low> PTH release > osteoclasts > bone breakdown > increase in calcium levels.

Question 11

Describe Neural Influences

Answer 11

Control of endocrine gland

Question 12

Hormonal

Answer 12

Control of the secretory activity of 1 endocrine gland by a hormone / OR neurohormone secreted by another endocrine gland.

Question 13

What are the major mechanisms of maintenance of blood hormone levels

Answer 13

FEEDBACK LOOPS

• Posivite feedback
• Negative Feedback

Question 14

How do Positive feedback loops maintain blood hormone levels?

Answer 14

Positive Feedback Loops:
(release of an additional hormone in response to a original hormone release)

This form of feedback is exhibited during childbirth. Whereby oxytocin is secreted by the pituitary gland, stimulating the uritine muscles to contract, encouraging the fetus to move towards the cervix.

Question 15

How do negative feedback loops maintain blood hormone levels?

Answer 15

Negative Feedback Loops: (inhibiting further hormone release due to adequate amounts of hormone)

E.g. release of glucocorticoid hormone released via the adrenal glands (stimulated via the pituitary gland and hypothalamus). As glucocorticoid levels increase in the blood, pituitary and hypothalamus reduce signaling to adrenal gland preventing overproduction of glucocorticoid)

Question 16

What are 10 regulatory functions of endocrine system?

Answer 16

1. Metabolism
   
   2. Food intake + digestion’tissue maturation
   3. Ion regulation
   4. Control of blood glucose
   5. Reproductive function control
   6. Uterine contractions
   7. Milk release
      
      8. Immune system regulation

Question 17

What are the functions of the Posterior Pituitary gland

Answer 17

Posterior Pituitary

1. ADH – increased water absorption (Target – kidneys) 
2. Oxytocin – increased uritine concentrations (target – uterus)

Question 18

What are the functions of the Anterior Pituitary Gland?

Answer 18

Anterior Pituitary Glands:
1. Growth Hormone – increased growth = increased amino acid uptale, breakdown of lipids, increased glycogen synthesis, blood glucose levels)

2. Thyroid Stimulating Hormone: increased thyroid hormonal secretion (target – thyroid gland) 
3. Adrenocorticotropic (ACTH): increased ACTH secretion (Target – adrenal cortex)
4. Lipotropins: Increased lipid breakdown (target – adipose tissue) 
5. Prolactin: Milk production in lactating women (Target Tissue: ovaries and mammary glands)

Question 19

What are the functions of the Hypothalamus?

Answer 19

Regulates secretions of anterior pituitary gland. Secretes and inhibits hormones directed to the anterior pituitary gland. And action potentials.

Question 20

Describe the hormones released from the Pituitary gland glands and summarise their functions in the body

Answer 20

Post Pituitary

• ADH (water retention)
• Oxytocin (contractions + milk ejection)

Anterior:

• Growth Hormone (growth, metabolism, protein uptake)
• Thyrotropin (thyroid hormones)
• ACTH (cortisol secretion)
• FH + FSH (production of gametes + reproductive hormones)
• Prolactin (stimulates milk production)

Question 21

Hormones released by Thyroid Gland

Answer 21

Thyroid Galnd:

• T3
• T4

Question 22

What does T3 and T4 do?

Answer 22

Functions:

• initiate protein synthesis
• increase rate of glucose, fat and protein metabolism
• increase body temp, and normal growth of tissues.
  4. Both T3 and T4: synthesis in thyroid follicles, are transported in the blood, bind with nuclear receptor molecules, secretion levels are regulated via TRH (via hypothalamus) TSH (via anterior pituitary gland) > all inhibiting secretion.

Question 23

What are the hormones released by the Parathyroid Gland

Answer 23

PTH (parathyroid hormone)

Question 24

What are the functions of PTH?

Answer 24

1. Increase blood calcium and PO4- levels
   
   2. Stimulate osteoclasts
   3. Promote calcium reabsorption
      
      4. Synthesis of vitamin D (increasing absorption of Ca and PO4)

Question 25

What hormones are released by the Adrenal Medlulla?

Answer 25

Epinephrine + Norepinephrine

Question 26

What are the functions of epinephrine?

Answer 26

Epinephrine: increasing BGL’s, increasing fat breakdown in adipose tissue, dilation of blood vessels in skeletal and cardiac muscles/

Question 27

What conditions result from hyposecretion?

Answer 27

Hyposecretion:

> Mineralocorticoids (aldosterone). Cause: removal of gland or loss of fucntion. Sym: hypoatremia (low blood levels of Na), Hypokalemia (high blood level of K+), low blood pressure, tremors. 

> Glucocorticoids (Cortisol). Cause: removal of glad or loss of function. Sym: low blood glucose levels (hypoglycemia), depressed immune system, ;loss of appetite, bronzed skin, in women decreased pubic and axillary hair.

Question 28

What conditions result from hypersecretion

Answer 28

> Mineralocorticoids (aldesterone), Causes: tumor in gland or aldosteronism. Sym: slight hypernatremia (high levels of Na), Hypokalemia (low blood levels of K), high blood pressure, weakness o skeletal muscles acidic urine)

> Glucocorticoids (cortisol). Causes: tumor in gland or cushing syndrom (high cortisol and androgens) . Symphyperlycemia (high blood glycose levels), depressed immune system, depression. 

> Androgens: Causes: tumor in gland or adrenogenital syndrome. Sym: Excessive facial and body hair, acne, increased sex drive, regression of breast tissue, loss of regular menses.

Question 29

What are the effects of aging on the endocrine system?

Answer 29

Aging results in a gradual decreases in secretion rates for most, but not all hormones. Some of these decreases are related to a gradual decrease in physical activity.

Hormones decreasing:
GH, melatonin, thyroid hormones (T3 and T4 slowly decreasing), reproductive hormone, thymosin. Fewer mimmature lymphocytes mature and are functional, the immune system is less active; resulting in a increased susceptability to infection and cancer.

Question 30

What hormone remains despite ones age?

Answer 30

Parathyroid hormone” regulates blood glucose levels