A+P L Midterm PT 1

Question 1

Compare and contrast how the nervous and endocrine systems communicate with their target cells.

Answer 1

Nervous System:
- Communication involves electrical signals (action potentials) and chemical signals (neurotransmitters).
- Speed: Fast and immediate response.
- Target: Specific, often localized (e.g., muscles or glands).
- Duration: Short-lived effects.

Endocrine System:
- Communication involves hormones released into the bloodstream.
- Speed: Slower response compared to the nervous system.
- Target: Can impact numerous cells or organs across the body.
- Duration: Longer-lasting effects.

Question 2

Explain how a hormone can modify the activity of its target cells. Provide examples of different mechanisms of hormonal action.

Question 3

List the seven hormones secreted by the anterior pituitary gland and describe their primary functions.

Answer 3

1. Growth Hormone (GH)- Stimulates growth and cell regeneration.
2. Thyroid-stimulating hormone (TSH)- Stimulates the thyroid gland to regulate metabolism.
3. Adrenocorticotropic Hormone (ACTH)- Stimulates the adrenal glands to release cortisol.
4. Follicle-stimulating hormone (FSH)- Stimulates egg and sperm production.
5. Luteinizing Hormone (LH)- Triggers ovulation and stimulates sex hormone production.
6. Prolactin (PRL)- Stimulates milk production in breastfeeding.
7. Melanocyte-stimulating hormone (MSH)- Regulates skin pigmentation.

Question 4

Identify the two hormones released by the posterior pituitary gland and explain their physiological roles.

Answer 4

Antidiuretic Hormone (ADH), also known as Vasopressin- Helps regulate the balance of water in the body. It acts on the kidneys to promote water reabsorption, reducing the amount of water excreted in urine. This helps conserve water and maintain proper hydration and blood pressure levels.

Physiological effects- When the body is dehydrated ADH is released to encourage the kidneys to retain more water, increasing blood volume and decreasing urine output.

Oxytocin is involved in childbirth and lactation. It stimulates uterine contractions during labor and helps with milk ejection during breastfeeding.

Physiological Effects- Promotes strong contractions of the uterus to help deliver the baby. After birth, it stimulates the mammary glands to release milk in response to the baby’s sucking.

Question 5

What are the five primary effects of thyroid hormones on the body?

Answer 5

1. Regulate Metabolism: Increase the body’s rate of metabolism, helping to produce energy.
2. Increase Heart Rate: Stimulate the heart to beat faster and stronger.
3. Promote Growth and Development: Essential for normal growth and development, especially in children.
4. Enhance Protein Synthesis: Aid in the production of proteins, supporting tissue growth and repair.
5. Regulate Body Temperature: Help maintain normal body temperature by increasing heat production.

Question 6

Describe how calcitonin and parathyroid hormone regulate blood calcium levels.

Answer 6

Calcitonin:
- Released by the thyroid gland when calcium levels are high.
- It lowers blood calcium by promoting calcium deposition in bones and reducing calcium reabsorption by the kidneys.

Parathyroid Hormone (PTH):
- Released by the parathyroid glands when calcium levels are low.
- It raises blood calcium by stimulating calcium release from bones, increasing calcium absorption in the intestines, and reducing calcium excretion by the kidneys.

Question 7

Name the three zones of the adrenal cortex and specify the types of hormones each zone produces.

Answer 7

Zona Glomerulosa:
Produces mineralocorticoids (e.g., aldosterone), which help regulate sodium and potassium levels and blood pressure.

Zona fasciculata:
Produces glucocorticoids (e.g., cortisol), which regulate metabolism, reduce inflammation, and help the body respond to stress.

Zona Reticularis:
Produces androgens (e.g., testosterone), which contribute to the development of male characteristics and influence other bodily functions.

Question 8

Identify the two hormones released by the kidneys and explain their physiological significance.

Answer 8

Erythropoietin (EPO): Stimulates the production of red blood cells in the bone marrow in response to low oxygen levels in the blood.

Renin: Activates the renin-angiotensin-aldosterone system (RAAS), which helps regulate blood pressure and fluid balance by increasing sodium and water retention in the kidneys.

Question 9

What four types of endocrine cells are found in the pancreas? Name the hormone each cell type produces and describe its function.

Answer 9

Alpha cells:
Hormone: Glucagon
Function: Increases blood glucose levels by promoting the release of glucose from the liver.

Beta cells:
Hormone: Insulin
Function: Lowers blood glucose levels by helping cells absorb glucose for energy.

Delta cells:
Hormone: Somatostatin
Function: Inhibits the release of both insulin and glucagon, helping regulate their balance.

PP cells (F cells):
Hormone: Pancreatic polypeptide
Function: Regulates the secretion of pancreatic enzymes and helps control appetite.