nervous system

Question 1

local communication types

Answer 1

• neural - neurotransmission
• aprocrine
• parocrine
• gap junctions

Question 2

long distance communication

Answer 2

• hormones
• neural communication = neurohormones

Question 3

3 types of hormones

Answer 3

• peptide hormones
• amines
• steroids

Question 4

peptide hormones

Answer 4

• amino acid chains of various lengths
• lipophobic (hydrophillic)
• transported freely in blood but cannot cross plasma membrane (soluble in water)

Question 5

peptide hormones

Answer 5

• amino acid chains of various lengths
• lipophobic (hydrophillic)
• transported freely in blood but cannot cross plasma membrane (soluble in water)

Question 6

steroids

Answer 6

• all derived from cholesterol
• bound to carrier protein in blood :. exends half life
• lipophillic (hydrophibic)
• can cross plasma membrane –> bind to receptors in cytoplasm or nucleus –> alters protein synthesis

Question 7

amines

Answer 7

• amino acids with modified groups

Question 8

amines

Answer 8

• amino acids with modified groups

Question 9

types of cell surface receptors

Answer 9

• receptor channels –> ligand binds to the receptor and opens and closes the channel
• receptor enzymes –> receptor region on the extracellular surface; enzyme region on cytoplasmic side.
• G protein coupled receptors –> cross phospholipid bilayer 7 times
• integrins –> membrane spanning protein

Question 10

how are hormonal secretions stimulated

Answer 10

• hormonal –> stimulation from hormones
• neural –> stimulation from electrochemical signalling
• humoral –> level of susbtance (e.g. ions) in the blood. –> secretes hormones in response

Question 11

how are hormonal secretions regulated

Answer 11

negative and postive feedback

Question 12

patterns of hormone secretion

Answer 12

• circadian
• monthly
• episodic –> increase hormone in response to stimulus
• seasonal
• pulse day/night

Question 13

factors affecting hormone concentration in plasma

Answer 13

• rate of secretion
• reate of binding to receptors - to carrier proteins
• rate of metabolism - activation/degradation.

Question 14

role of calcium in body

Answer 14

• excitability of nerves
• muscle contraction (cardiac and skeletal muscle - excitation-contraction coupling)
• neurotransmitter release
• blood clotting
• bone and teeth structure and strength

Question 15

location of the parathyroid gland

Answer 15

• 4 rice grain-sized glands on the posterior surface of the thyroid glands

Question 16

how does vit D influence calcium absorption

Answer 16

• Vit D is steroid hormone (produced by cholesterol)

1. Vit D binds to Vit D receptors (VDR) in the nucleus –> expression of specific gene products
2. This increases calcium uptake and translocation across intestinal epithelia as active forms of Vit D (calcitriol) stimulates the synthesis of calcium binding proteins - aiding transportation of Calcium across epithelia.