Exam 3 content

Question 1

Are neurotransmitters considered hormones?

Answer 1

Yes, but they specifically act on target cells through the synaptic cleft.

Question 2

Define a hormone:

Answer 2

A secreted molecule travels to target cells and exerts some effect based on an interaction with the receptor. Can go through blood or act locally. Can act as neurotransmitters or hormones based on the context.

Question 3

Compare the endocrine system to the nervous system (two main control systems)

Answer 3

The nervous system is much faster and reaches fewer neurons. The endocrine system is much slower and reaches more cells.

Question 4

In the endocrine system, organs are related _______ but not ________

Answer 4

functionally, physically

Question 5

Insulin
Type of molecule (e.g. steroid, peptide) and solubility (water or lipid)
Cell type that produces hormone
Stimulus for secretion
What is the receptor (key properties of receptor)
What effect does hormones have?

Answer 5

• Insulin is a water-soluble peptide hormone that binds a transmembrane receptor
• Produced by beta islet cells in the pancreas, which are sensitive to high plasma glucose levels
• Receptors include skeletal muscle, adipocytes, and liver cells.
  -Functions to decrease the amount of plasma glucose in the blood through absorption into liver, skeletal muscle, and adipocytes.

Question 6

What is blood plasma?

Answer 6

Blood plasma is the non-cellular portion of blood

Question 7

Describe how beta islet cells function as a sensor and controller

Answer 7

• Initially, high plasma glucose levels drives glucose transport via Glut2 into beta islet cells
• This influx of glucose leads to an increase in metabolic activity and an increase in ATP produced by the metabolism.ATP binding to potassium channels, blocking the release of potassium and increasing membrane potential
• This process opens voltage gated Calcium channels
• This leads to the exocytosis of insulin which is released in the blood

Question 8

Outline the negative feedback loop for the hormone insulin

Answer 8

(drawing)

Question 9

Describe the effect of actuating signal (insulin) on effector cells. FOR muscle and adipocytes (fat cells)

Answer 9

-Insulin is a water-soluble peptide hormone that binds a transmembrane receptor
-This stimulates glucose exocytosis and increases glucose uptake
- When insulin levels are low, Glut4 endocytosis is favored, reducing membrane permeability to glucose

Question 10

Describe the effect of actuating signal (insulin) on effector cells. FOR liver cells

Answer 10

-Insulin is a peptide hormone that binds a transmembrane receptor
-This stimulates glycogen production from glucose,
- Leading to an influx of glucose from Glut2 (which is not under hormonal control).

Question 11

Outline the negative feedback loop for the hormone insulin

Answer 11

(drawing)

Question 12

Glucagon
Type of molecule (e.g. steroid, peptide) and solubility (water or lipid)
Cell type that produces hormone
Stimulus for secretion
What is the receptor (key properties of receptor)
What effect does hormones have?

Answer 12

-Water soluble
-Produced by alpha islet cells in the pancreas
-Sensitive to low glucose plasma levels
- Receptor is liver cells, has the impact of raising blood plasma glucose by releasing glucose held in stores

Question 13

For Glut 2 in the liver, is the channel under hormonal control?

Answer 13

No, the channel is not under hormonal control

Question 14

Describe the effect of the actuating signal (glucagon) on effector cells FOR liver cells

Answer 14

Glucagon is a water-soluble peptide hormone that binds a g-protein coupled transmembrane receptor. This binding leads to glucose production from glycogen (glycogenolysis) and the release of glucose from the cell via Glut2

Question 15

_________ represents the production of glycogen from glucose, _______ represents the production of glucose from glyogen

Answer 15

• gluconeogenesis
• glycogenolysis

Question 16

Describe diabetes mellitus. What are the symptoms?

Answer 16

Plasma glucose levels remain high. There are numerous possible symptoms, but two prominent examples include high volume of urine and thirst. There is too much glucose in blood plasma, consequently more glucose than typical enters the Bowman’s Capsule of a nephron. There are more solutes in the filtrate, changing osmotic balance such that less water is absorbed through Osmosis.

Question 17

Characterize the two kinds of diabetes mellitus

Answer 17

Type 1: there is a problem with beta islet cells such that no insulin is produced
Type 2: insulin insensitivity in skeletal, adipocytes, or liver cells.

Question 18

Production of calcium effectively ______ it’s own regulatory system by binding to ______, inhibiting the release of _______

Answer 18

turns off, CaSR, PTH

Question 19

Describe the negative feedback loop involved in the control of plasma Ca2+

Answer 19

(draw)
So, overall, we increase plasma levels of calcium by increasing the amount we absorb in the intestine, increasing the amount we reabsorbed from filtrate, and by breaking down bone tissue and calcium stored in bone.

Question 20

Describe the actions of the effectors in the chart (bone) in response to low calcium levels and the release of PTH

Answer 20

• 99% of the calcium in our bodies is stored in our bones
• PTH acts on osteoclasts via PTH receptors
• PTH receptors are g-protein coupled receptors
• Osteoclasts break down calcified extracellular matrix in bone tissue, which releases Ca2+ into blood plasma

Question 21

Describe the actions of the effectors in the chart (distal tubule and collecting duct) in response to low calcium levels and the release of PTH

Answer 21

• PTH binds PTH receptors on epithelial cells to increase Ca2+ reabsorption by the kidney.

Question 22

Describe the actions of the effectors in the chart (proximal tubule) in response to low calcium levels and the release of PTH

Answer 22

• PTH stimulates release of 1,25 dihydroxy vitamin D (1,25(OH)2D), a lipid soluble hormone which acts on receptors in the intestine to increase Ca2+ absorption

Question 23

PTH
Type of molecule (e.g. steroid, peptide) and solubility (water or lipid)
Cell type that produces hormone
Stimulus for secretion
What is the receptor (key properties of receptor)
What effect does hormones have?

Answer 23

Water-soluble
Parathyroid gland cells, which express calcium sensing receptor
Low calcium levels in blood plasma
Increasing blood plasma levels of calcium by increasing amount absorbed in intestine, amount absorbed from filtrate, and by breaking down bone tissue and releasing calcium stored in bone.

Question 24

Describe the hypothalamus and pituitary: regulation of cortisol

Answer 24

• Corticotropin Releasing Hormone (CRH) is released in the hypothalamus
• This leads to Adrenocorticotropic Hormone (ACTH) release from the anterior pituitary
  -And this leads to cortisol being released from the adrenal glands

Question 25

CRH and ACTH are both water-soluble peptide hormones that bind to ________, ______ is a lipid-soluble steroid hormone not that dissimilar in structure to

Answer 25

-g-protein coupled receptors
-cortisol
-1,25 dihydroxy vitamin D

Question 26

Describe the key physiological changes associated with cortisol

Answer 26

• Stimulation of liver cell uptake of amino acids
• Stimulation of triglyceride breakdown
• Inhibition of inflammation
• Inhibition of nonessential functions

Question 27

Similar to _________, Cortisol limits its own release

Answer 27

Calcium

Question 28

What are the two main hormones associated with human growth from the hypothalamus and what effects do they have, respectively?

Answer 28

Growth hormone-releasing hormone (GHRH) –> increased protein synthesis, cell differentiation and division, notably CAUSES secretion of IGF1 from the liver which limits production
Somatostatin (SST)

Question 29

IGF1, a result of the _______, has a _____ effect on GHRH, and a _____ effect on somatostatin

Answer 29

Growth Hormone, negative, positive

Question 30

GH is specifically released from the ______

Answer 30

Anterior Pituitary

Question 31

All hormones in the growth hormone pathway are

Answer 31

water-soluble

Question 32

2. GHRH and SST act via _________3. GH and IGF-1 act via
   different kinds of
   _______________________

Answer 32

G-coupled protein receptors
transmembrane receptor
proteins.

Question 33

Describe the functional importance of the posterior pituitary in the endocrine system

Answer 33

Release of oxytocin and and ADH into bloodstream