A&P II - Wk. 2 Endocrine System Labs + notes

Q: What hormone does the anterior pituitary gland secrete, and what is its effect?

A: Growth hormone → Stimulates overall cellular growth and division

Q: What hormone does the posterior pituitary gland release, and what are their effects?

• Oxytocin → Stimulates uterine contraction during labor

Q: What hormone does the Hypothalamus release, and what are their effects?

ADH & OT → Regulates anterior pituitary gland hormone release Makes hormones for posterior

pituitary gland to release

Q: What hormone does the pineal gland release, and what is its effect?

A: Melatonin → Regulates the biological clock

Q: What hormones does the thyroid gland secrete, and what are their effects?

A: T3 & T4 → Increase cellular metabolism

Q: What hormone does the thymus release, and what is its effect?

A: Thymosin → Directs the maturation of T lymphocytes

Q: What hormone do the adrenal glands release, and what is its effect?

A: Epinephrine → Prolongs and enhances the sympathetic “fight-or-flight” response

Q: What hormone does the pancreas release, and what is its effect?

A: Insulin → Decreases blood glucose levels

Q: What is hormonal control of hormone release? Give an example.

A: One hormone stimulates release of another (e.g., thyroid hormone released in response to TSH)

Q: What is humoral control of hormone release? Give an example.

A: Hormone release triggered by changing blood concentrations (e.g., insulin released when glucose rises)

Q: What is nervous system control of hormone release? Give an example.

A: Direct stimulation by nerves (e.g., epinephrine released by sympathetic nervous system activation)

Q: How are biogenic amines made? Are they water- or lipid-soluble?

A: Derived from modified amino acids; water-soluble

Q: Give examples of biogenic amines.

A: Epinephrine and norepinephrine

Q: How are protein hormones made? Are they water- or lipid-soluble?

A: Chains of amino acids; water-soluble

Q: Give examples of protein hormones.

A: Insulin, glucagon

Q: How are steroid hormones made? Are they water- or lipid-soluble?

A: Derived from cholesterol; lipid-soluble

Q: Give examples of steroid hormones.

A: Testosterone, progesterone

Q: Does insulin require a carrier protein in the blood?

A: No – insulin is water-soluble

Q: Does estrogen require a carrier protein in the blood?

A: Yes – estrogen is lipid-soluble

The hormone ____ (released by the pancreas) and is water‐soluble.

insulin

he ____ estrogen (released by the ovaries) and is lipid‐soluble

hormone

Q: Where are receptors for lipid-soluble hormones located?

A: Cytosol or nucleus

Q: Where are receptors for water-soluble hormones located?

A: On the cell surface

When a _______ hormone attaches to its receptor, a hormone‐receptor complex (HRC) forms.

lipid‐soluble

Q: What small holes does the HRC pass through to enter the nucleus?

A: Nuclear pores

Q: What macromolecule does the HRC attach to inside the nucleus?

DNA

What happens in the cell in response to this HRC attachment?

A: mRNA transcription → protein synthesis → altered cell function

When a water‐soluble hormone attaches to its receptor, it uses a secondary messenger system to trigger changes inside the target cell.

What is the name of the small protein that is activated by the receptor (by adding a GTP molecule to it after the hormone has attached to it)?

A: G protein

Sometimes, the intracellular secondary messenger is made by the enzyme ?

adenylate cyclase.

How does adenylate cyclase become activated?

A: By an activated G protein

What does adenylate cyclase generate when it breaks down ATP? (This is the secondary messenger!)

cAMP

What is the effect of this secondary messenger in the target cell?

A: Activates protein kinase A → phosphorylates proteins → changes metabolism & gene expression

Sometimes, the intracellular secondary messenger is made by the enzyme _____ C.

phospholipase

How does phospholipase c become activated?

A: By an activated G protein

When phospholipase C is activated, it makes 2 molecules. What are they?

A: IP₃ and DAG

c. Which molecule leads to the release of calcium from the endoplasmic reticulum in the cell?

IP₃

d. What protein binds to calcium, allowing it to then activate a protein kinase enzyme?

Calmodulin

e. What molecule activates specifically activates protein kinase C?

A: DAG (with Ca²⁺ help)

Q: When hormone levels are high, receptors: ↑ or ↓? What is this process called

Decrease - downregulation

Q: When hormone levels are low, receptors: ↑ or ↓? - what is this process called?

Increase - upregulation

Q: What is a synergistic effect? Give an example.

A: Two hormones amplify each other’s effects (e.g., FSH + testosterone)

Q: What is a permissive effect? Give an example.

A: One hormone enables another to act (e.g., prolactin + oxytocin)

Q: What is an antagonistic effect? Give an example.

A: Two hormones have opposite effects (e.g., glucagon vs. insulin)

Q: What organ metabolizes many hormones (e.g., estrogen)?

A: Liver

Q: What 3 waste products eliminate metabolized hormones?

A: Bile, feces, urine