Term
| Who is known as the father of physiology? What did he recognize? |
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Definition
Claude Bernard (1813-1878)
He recognized the process of homeostasis, that a process provides stable conditions for body's cells. |
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Term
| What is Walter Cannon (1871-1945) known for? |
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Definition
He coined the term "homeostasis" to describe the relative stability of the
body's internal environment. When looking at the roots of the word, it's confusing because the body is changing and dynamic. |
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Term
| What are the 3 things homeostatic control relies on? Briefly describe them. |
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Definition
1. SENSOR: constant monitoring
2. INTEGRATING CENTRE: coordinates response
3. RESPONSE SYSTEM: causes a change |
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Term
| Most physiological processes operate by a negative feedback loop, name one process that operates by a POSITIVE feedback loop. |
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Definition
| The birthing process --> the release of oxytocin. |
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Term
| Homeostasis is maintained largely by which system? |
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Definition
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Term
| What happens when a hormone has hyper-function? |
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Definition
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Term
| What happens when a hormone has hypo-function? |
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Definition
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Term
| What happens when a cell develops resistance to a hormone? |
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Definition
| Fully functional hormone has reduced effect |
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Term
| Define an endocrine gland. |
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Definition
| a tissue which secretes a substance into the blood stream. The substance travels via the blood to influence a target cell. |
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Term
| Describe the Minkowski experiment (1889). |
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Definition
The Minkowski experiment (1889) discovered the role of pancreatic tissue in diabetes.
- They surgically removed the pancreas from a dog and observed that the dog developed symptoms of diabetes mellitus.
- They then implanted pieces of pancreas under the skin, and observed that the dog no longer exhibited symptoms.
o Found that something in the pancreas prevents diabetes mellitus symptoms |
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Term
| What did Banting & Best discover in 1921? |
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Definition
They discovered the actual antidiabetic substance from pancreatic extracts (aka INSULIN)!
- Injected insulin prevents symptoms, and implanted tissue no longer had to be used |
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Term
| Where is insulin substance formed? What does it do? |
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Definition
Insulin is a:
- Peptide hormone secreted from the islets of Langerhans (beta cells) in the pancreas
- Promotes absorbtion of glucose from blood to skeletal muscle and fat tissue |
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Term
| Describe the difference between the inactive and active form of insulin. |
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Definition
- Its inactive form is a hexomer, with a zinc ion and histidine residues holding the monomers together
- Its active form is a monomer |
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Term
| Name the 4 classes of hormones listed in class. |
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Definition
1. Most hormones are proteins and polypeptides (<100 amino acids)
2. Steroids (cholesterol derivatives)
3. Amines (catecholamines)
4. Amines (thyroid) |
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Term
| What is the autocrine hormonal effect? |
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Definition
| Hormone is released and acts on the same cell |
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Term
| What is the paracrine hormonal effect? |
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Definition
| Release of hormone from secretory cell to affect nearby target cells |
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Term
| What is the endocrine hormonal effect? |
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Definition
| The release of hormone(s) from a secretory cell, which travels through the bloodstream to a target cell |
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Term
Describe the ________ of a protein hormone.
a) synthesis
b) storage
c) release from cell
d) transport in blood
e) half-life
f) an example |
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Definition
a) made in advance
b) stored in secretory vesicles
c) released by exocytosis
d) transported dissolved in the plasma
e) short half-life
f) example: insulin |
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Term
Describe the ________ of a steroid hormone.
a) synthesis
b) storage
c) release from cell
d) transport in blood
e) half-life
f) an example |
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Definition
a) made on demand
b) not stored
c) released by diffusion (lipophilic)
d) transported bound to carrier protein
e) long half-life
f) example: estrogen/androgen |
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Term
Describe the ________ of a catacholamine hormone.
a) synthesis
b) storage
c) release from cell
d) transport in blood
e) half-life
f) an example |
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Definition
a) made in advance
b) stored in secretory vesicles
c) released by exocytosis
d) transported dissolved in the plasma
e) short half-life
f) example: epinephrine/norepinephrine |
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Term
Describe the ________ of a thyroid (amine) hormone.
a) synthesis
b) storage
c) release from cell
d) transport in blood
e) half-life
f) an example |
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Definition
a) made in advance
b) stored in secretory vesicles
c) released by diffusion (lipophilic)
d) transported bound to carrier protein
e) long half-life
f) example: Thyroxine (T4) |
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Term
True/False
1. Receptors for most hormones are found on the cell membrane
2. Steroid hormone receptors are found in the cytoplasm
3. Thyroid hormone receptors are found in the nucleus |
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Definition
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Term
| Describe the Adenylate Cyclase (AC) Pathway |
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Definition
1. Hormone + Receptor causes G-protein to dissociate
2. Alpha subunit of G-protein (Gs) activates adenylate cyclase
3. AC catalyzes the production of cAMP
4. cAMP removes the regulatory unit from protein kinase A (PKA)
5. PKA activates other molecules
6. Hormonal response |
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Term
What receptor does epinephrine bind to in order to cause an increase in blood sugar?
What main proteins does this pathway involve? |
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Definition
beta-adrenergic receptors
alpha (Gs) subunit of G-protein, adenylyl cyclase, cAMP, protein kinase A, phospholipase, glycogen, G6P --> glucose |
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Term
What receptor does epinephrine bind to in order to cause an increase in cytoplasmic calcium levels?
What main proteins does this pathway involve? |
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Definition
ALPHA-adrenergic receptors
alpha (Gq) subunit of G-protein, Phospholipase C, IP3, |
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Term
| True/False: Thyroid hormone receptors are only found in the cytoplasm |
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Definition
| FALSE! Thyroid hormone receptors are only found in the nucleus. |
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Term
| Describe the transmembrane receptor pathway for steroid hormones. |
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Definition
1. Steroid hormone (eg estrogen/androgen) are transported via bloodstream to target cell, bound to a carrier protein
2. Hormone unbinds and diffuses across cell membrane
3. Hormone binds to cell cytoplasm receptor
4. Hormone-receptor complex translocates to the nucleus, binds DNA (acts as a transcription factor)
5. This stimulates gene transcription (mRNA) -> protein products -> response
It could also bind to the receptor in the nucleus, and the complex could bind to a hormone response element on DNA. This causes an increase in production of mRNA and ultimately protein. |
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Term
| Describe the transmembrane receptor pathway for thyroid hormones. |
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Definition
1. Thyroid hormone (eg T4) are transported via bloodstream to target cell, bound to a carrier protein
2. Unbinds and diffuses across cell membrane
3. All T4 is converted into T3 (triiodothyoine) in the cytoplasm
4. T3 uses binding proteins to enter the nucleus, where it binds to its receptor
5. The hormone-receptor complex binds DNA
6. Transcribes new mRNA -> protein -> response |
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Term
| Describe how the hypothalamus causes a reaction that leads to tissue response. |
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Definition
1. Hypothalamus releases hormone 1 (H1) into blood vessel
2. H1 causes anterior pituitary to release H2 into the main circulation
3. H2 reaches target tissue and either:
- releases H3 into main circulation if target is a peripheral endocrine gland (eg thyroid) -> H3 causes tissue response
- or if target tissue is non-endocrine, H2 causes direct tissue response |
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Term
| The anterior pituitary (controlled by the hypothalamus) controls the release of what hormones? (5) |
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Definition
- Prolactin (mammary gland)
- Growth hormone (bone, muscle, and adipose tissue)
- TSH (thyroid)
- ACTH (adrenal cortex)
- Gonadotrophins (ovary and testis) -> FSH & LH |
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Term
| List the 7 hypothalamic hormones/factors noted in class. |
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Definition
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Dopamine (PIH)
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Prolactin Inhibiting Hormone
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PRH
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Prolactin Releasing Hormone
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TRH
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Thyrotropin Releasing Hormone
- Regulates the secretion of thyroid stimulating hormone (TSH)
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CRH
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Corticotrophin releasing hormone
- Regulates secretion of adrenocorticotropic hormone (ACTH)
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GHIH
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Somatostatin
- Inhibits secretion of growth hormone (GH)
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GHRH
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Growth hormone releasing hormone
- Stimulates secretion of GH
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GnRH
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Gonadotrophin releasing hormone
- Regulates the secretion of:
o gonadotrophin releasing hormones
o luteinizing hormone (LH), and
o follicle stimulating hormone (FSH)
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Term
Label the following image of the large ruminant anterior pituitary
[image] |
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Definition
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