Endocrine System

Question 1

What is endocrine system responsible for:

Answer 1

controls large number of homeostatic variables.
mediates comm at slow rate but produces a more widespread effect
- lots of interactions with nervous system
- it regulated development, growth, & reproduction
(what we look like)

Question 2

Study of endocrine system?

Answer 2

Endocrinology

Question 3

Many orders that effect humans involve the endocrine system

Answer 3

endocrine system malfunction.

drugs are used to treat these disorders by mimicking or blocking actions of hormones

Question 4

Hormone:

Answer 4

chemical messengers that are released into the blood stream to act on an organ to control body functions

Question 5

Tropic Hormone:

Answer 5

influence activities of other endocrine glands

Question 6

Endocrine Cell:

Answer 6

cells that perform various physiological functions

Question 7

Endocrine glands:

Answer 7

secretory organs where hormones are released

Question 8

Target Tissues:

Answer 8

tissues that usually located away from endocrine organ where hormones travel through systemic circulation and binds to receptor associated

Question 9

differences between endocrine & nervous system

Answer 9

• response time slower in endocrine due to time taken for hormone synthesis, secretion, transport through blood stream, receptor binding, effect on target tissues
• all cells are exposed to hormones from endocrine system (as they are transported via blood)

Question 10

Where are the major Endocrine Glands:

Answer 10

Brain, Digestive Tract, Heart, Kidneys

Question 11

How some hormones interact with carrier proteins:

Answer 11

• most hormones have multiple target tissues
• some hormones bind to carrier protein and are transported in the blood via complexes
• these complexes are useful as they provide readily available supply of hormone within circulation
• acts as buffer & smooths out spikes in hormone secretion
• makes hormone less likely to be metabolized by enzymes in blood, liver, kidneys

Question 12

largest & most physiologically important hormones:

Answer 12

Peptide hormones
- insulin (from pancreas)
- growth hormone (pituitary gland)
- calcitonin (thyroid gland)
-

Question 13

Peptide Hormones:

Answer 13

• consists of amino acids which vary in size from 3-191 amino acids
• peptide hormones synthesize in rough ER & are passed onto Golgi apparatus for further processing
• they’re packed in membrane secretory vesicles until released
• after exposed to appropriate triggers, the hormone is secreted by exocytosis

Question 14

How do peptide hormone receptors produce responses in target cells

Answer 14

• they circulate in bloodstream, not bound to carrier protein
• they enter extracellular space binding to specific receptor associated with target tissue
• Hormone binding triggers a cascade of intracellular events, producing response in target cell

Question 15

Know the molecular pathway responsible for the synthesis of noradrenaline in most catecholamine secreting cells and how this is different in the adrenal medulla.

Answer 15

Tyrosine is enzymatically converted to dihydroxyl phenylalanine (L-DOPA) to dopamine (DA). Da is then transported into membrane-bound secretory vesicles where enzymes required for conversion to noradrenaline. They are t hen stored in vesicles until released by exocytosis

Question 16

How are steroid hormones synthesized?

Answer 16

• derivatives of cholesterol
• 80% of cholesterol is obtained from dietary intake and taken up by cells through receptor-mediated endocytosis and the remainder is synthesied

Question 17

Peptide hormones:

Answer 17

Insulin, Growth Hormone, Glucagon, Vasopressin, Parathyroid hormone, calcitonin, secretin

Question 18

Steroid hormones:

Answer 18

cortisol, aldosterone, sex hormones,

Question 19

how do steroid hormones produce responses in target cells:

Answer 19

• in blood they bind to carrier proteins which are specific
• bind to specific receptor in cytoplasm
• then diffuses into nucleus & binds to DNA sequences
• this up-regulates the transcription of specific genes & synthesis of proteins to mediate the response in target tissues

Question 20

circadian rhythm

Answer 20

Cardiac rhythm produces cyclical change in hormone secretion, such as cortisol, growth hormone, and melatonin

Question 21

Negative Feedback In Hormone Control:

Answer 21

if conc of hormone increases, level of negative feedback increases as a result amount of hormone produced declines
if hormone declines, decline, neg feedback decline so hormone secretion increases & restores status

Question 22

Positive Feedback in Hormone Control:

Answer 22

dramatic increases in hormonal secretion that eventuates is usually required when reaching well defined end point
e.g. oestrogen has on gonadotropin secretion during the ovulatory phase of the menstrual cycle in females

Question 23

Human growth & endocrine system:

Answer 23

• progressive process regulated by endocrine system
• size of person is predetermined at birth
• some variables include: availability of amino acids for protein synthesis, calcium for bone growth, energy for cellular processes

Question 24

Macroscopic Processes involved in growth:

Answer 24

• longitudinal growth: lengthening of somatic tissues (bone, muscle, tendons)
• Radial Growth: lengthening of somatic tissues and other organs

Question 25

Cellular Processes Involved in Growth:

Answer 25

• Hyperplasia: increases in cell number

- Hypertrophy: increases in cell size