BIOM PART TWO - Lecture 1

Question 1

Who was Claude Bernard?

Answer 1

The father of modern physiology

Question 2

What did Claude Bernard suggest?

Answer 2

Our internal environment remains remarkably constant despite changes in the external milieu

(provides stable conditions for cells in the body)

Question 3

What did Walter Cannon suggest?

Answer 3

Coined the term “homeostasis” to describe the relative stability of the internal environment

Question 4

What is the general process of homeostasis?

Answer 4

Sensor –> Integration/Control Center —> Effector

Question 5

What does a sensor do?

Answer 5

Detect shift in physiological variable outside normal range

Question 6

What does integration/control centre do?

Answer 6

Sets normal range

Question 7

What does an effector do?

Answer 7

Return to normal

Question 8

What direction is Homeostasis going in?

Answer 8

A negative direction (constant negative feedback loops)

Question 9

What does Homeostatic control rely on?

Answer 9

Sensor: constantly monitors

Integrating Centre: coordinates

Response System: changes

Question 10

What do most systems operate in?

Answer 10

A negative feedback manner

Question 11

What are some major regulatory systems?

Answer 11

• Skin
• Cardiovascular
• Renal
• Digestive
• Respiratory
• Musclo-Skeletal

Question 12

What are some regulated factors?

Answer 12

Water, pH, Oxygen, CO2, temperature

Question 13

What is Regulation?

Answer 13

Homeostasis and Maintenance of Metabolic Processes

Question 14

What is Homeostasis maintained by?

Answer 14

The endocrine system

Question 15

What is Diabetes an example of?

Answer 15

Defined by a loss of homeostasis

Question 16

What are examples of endocrine disorders?

Answer 16

Diabetes mellitus: 6th leading cause of death

Thyroid Diseases

Endocrine Ovarian Disorders

Question 17

What is Hyper Function?

Answer 17

Too much hormone

Question 18

What is Hypo function?

Answer 18

To little hormone

Question 19

What is Resistance?

Answer 19

Too little effect

Question 20

What does hormone mean?

Answer 20

To excite or arouse

Question 21

What is endocrine gland?

Answer 21

A tissue which releases a substance into the bloodstream; this substance then travels via the blood to influence a target cell

Question 22

What was significant about the Classic Minkowski experiment?

Answer 22

The discovery of insulin

Question 23

What was the Classic Minkowski Experiment?

Answer 23

1.) Surgically remove pancreas in dog –> The dog developed symptoms of diabetes (excessive urine, thirst)

2.) Implanted a piece of pancreas under the skin –> prevented symptoms if diabetes (reversed effect)

*Noted that the pancreas has an important effect

Question 24

What did Banting and Best similarity discover?

Answer 24

Insulin

Question 25

What did Banting and Best do?

Answer 25

1.) Identified anti-diabetic substance in pancreatic extracts 2.) Injecting extracts prevents symptoms of diabetes (i.e, elevated blood glucose)

Question 26

What is Insulin?

Answer 26

Peptide hormone produced by beta cells of the pancreas

Question 27

What does Insulin promote?

Answer 27

Absorption of glucose from blood to skeletal muscle and fat tissue

Question 28

What is the inactive form of Insulin?

Answer 28

Hexamer, Zinc Ion, and Histidine Residues

Question 29

What is the active form of Insulin?

Answer 29

Monomer

Question 30

What makes a chemical a hormone?

Answer 30

1.) Proteins and Polypeptides (<100 amino acids) 2.) Steroids (cholesterol derivatives) 3.) Glycoproteins 4.) Amines (catecholamines or thyroid)

Question 31

What are the level of effects?

Answer 31

Autocrine Paracrine Endocrine

Question 32

What is Autocrine?

Answer 32

Acts on itself

Question 33

What is Paracrine?

Answer 33

Acting on a cell nearby

Question 34

What is Endocrine?

Answer 34

Go through blood in order to release target

Question 35

What do hormones bind to?

Answer 35

Receptors in target cells

Question 36

What do receptors have a high speciality for?

Answer 36

A particular hormone (non specific binding can occur - eg, hormone overspill)

Question 37

What is there a continuous turn-over of?

Answer 37

The receptor hormone complex (essential for any signalling system)

Question 38

Where are receptors for most hormones (peptide) found?

Answer 38

In the plasma membrane of target cells

Question 39

Where are receptors for steroid and thyroid hormones found?

Answer 39

Inside the target cell

Question 40

What do Catecholamines and peptide hormones bind to?

Answer 40

The extracellular domain of the receptor and activates one or more cytoplasmic signalling pathway

Question 41

What do cytoplasmic signalling pathways involve?

Answer 41

Phosphorylation and Enzyme Activation

Question 42

What do some of these pathways lead to

Answer 42

DNA/mRNA/proein pathway response; others have local effect in target cell

Question 43

What are the steps of the Adenylate Cyclase pathway?

Answer 43

1. Hormone and Receptor, G proteins dissociate 2. a-subunit activates AC 3. Catalyzes product of cAMP 4. Removes regulatory unit from PK 5. PK activates other molecules (hormonal response)

Question 44

What are the steps of the Epinephrine and Adenylate Cyclase?

Answer 44

1. Epinephrine binds to B-adrenergic receptor on liver cells 2. G proteins activated - subunit carrying GDP dissociates, GDP --> GTP 3. Subunit catalyzes adenyl cyclase which catalyzes ATP --> cAMP 4. cAMP activates PKA which activates phosphorylase 5. Phsophorylase converts glycogen to glucose-6-phosphate 6. Glucose-6-phosphate --> glucose (released from liver)

Question 45

Who were Robert Lefkowitz and Brian Kabila?

Answer 45

Won the 2012 Nobel prize in chemistry

Question 46

What did Robert and Brian determine?

Answer 46

How the billions of cells in our body sense their environments

Question 47

What type of receptor did they focus on?

Answer 47

G protein coupled receptors

Question 48

Why is understanding how these proteins work important?

Answer 48

It has been crucial to unravelling the complex network of signalling between cells

Question 49

What are the steps of the Phospholipase C-Ca2+ pathway?

Answer 49

1. Hormone + receptor, G protein dissociate 2. Activates PLC 3. Causes breakdown of membrane phospholipid to IP3 4. IP3 binds to ER 5. Release of stored Ca2+ into cytoplasm 6. Ca2+ activates other molecules (hormonal responses)

Question 50

What do alpha-adrenergic receptors do?

Answer 50

Activate phospholipase C (via Gq)

Question 51

What do beta adrenergic receptors activate?

Answer 51

Adenyl Cyclase (via Gs)

Question 52

What do G subunits fall into?

Answer 52

Several sub types: G(s) alpha, G(a) alpha, etc.

Question 53

What is the pathway of steroid hormone receptors?

Answer 53

1. Steroid Hormones (e.g, estrogen, androgen,) transported bound to carrier protein (lipophilic) 2. Steroid Hormone binds cell cytoplasm receptor 3. Translocates to the nucleus, binds to DNA (acts as a txn factor) 4. Stimulates gene transcription 5. Protein products 6. Response

Question 54

What are the mechanisms of Thyroid Receptors?

Answer 54

1. Thyroxine (T4) and Carrier Binding Protein 2.) T4 ---> T3 3.) T3 uses binding proteins to enter nucleus 4. Hormone-receptor complex binds DNA 5. New mRNA 6. Protein 7. Response