ENDO

Question 1

What is the Endocrine System?

Answer 1

The endocrine system is a visceral regulatory system that regulates various bodily functions using hormones. It is primarily responsible for maintaining homeostasis, influencing internal environments through a slow-acting humoral system (via the bloodstream).

Question 2

What are the functions of the Endocrine System?

Answer 2

The endocrine system regulates smooth and cardiac muscle activity, organs and glands, metabolism, growth and development, and reproduction.

Question 3

What is the regulatory goal of the Endocrine System?

Answer 3

To maintain homeostasis, which is the maintenance of a dynamically stable state within a system through internal regulatory processes.

Question 4

How does the Endocrine System differ from the Nervous System?

Answer 4

The Endocrine System influences the internal environment through humoral regulation, while the Nervous System influences the external environment through somatic motor and sensory innervation.

Question 5

What is the action speed and duration of the Endocrine System compared to the Nervous System?

Answer 5

The Endocrine System is slow acting with long-term effects, while the Nervous System is rapid acting with short-term effects.

Question 6

What is a negative feedback loop?

Answer 6

A negative feedback loop is a regulatory mechanism where the stimulus is inverse to the direction of regulation.

Question 7

Give an example of a negative feedback loop.

Answer 7

Blood glucose regulation: Too low glucose → Pancreas releases glucagon → Liver converts glycogen to glucose. Too high glucose → Pancreas releases insulin → Cells metabolize glucose, liver stores it as glycogen.

Question 8

What is a positive feedback loop?

Answer 8

A positive feedback loop is a regulatory mechanism where the stimulus is in the same direction as regulation.

Question 9

Give an example of a positive feedback loop.

Answer 9

Breastmilk production: This system amplifies a physiological effect.

Question 10

What are endocrine glands?

Answer 10

Endocrine glands are ductless glands that secrete hormones into the bloodstream.

Question 11

What are exocrine glands?

Answer 11

Exocrine glands are ducted glands that secrete products to specific sites.

Question 12

How are endocrine structures connected?

Answer 12

Endocrine structures communicate through the humoral system, where secreted products enter blood vessels.

Question 13

What are the types of hormones?

Answer 13

Hormones can be proteins/peptides, which are water-soluble and have surface receptors, or steroids, which are lipid-soluble and have nuclear receptors.

Question 14

What is autocrine hormone secretion?

Answer 14

Autocrine secretion is when the hormone acts on the same cell that secretes it.

Question 15

What is paracrine hormone secretion?

Answer 15

Paracrine secretion is when the hormone acts on neighboring cells.

Question 16

What is endocrine hormone secretion?

Answer 16

Endocrine secretion is when the hormone acts on distant cells.

Question 17

What is the role of the hypothalamus?

Answer 17

The hypothalamus integrates the nervous and endocrine systems and serves as a link between these systems.

Question 18

What are the functions of the hypothalamus?

Answer 18

The hypothalamus regulates body temperature, heart rate, blood pressure, appetite, electrolyte balance, thirst, sleep cycles, sex and reproduction, and aggression.

Question 19

What is the pituitary gland known as?

Answer 19

The pituitary gland is referred to as the ‘Master Gland’ because it regulates most other endocrine glands.

Question 20

What are the two lobes of the pituitary gland?

Answer 20

The pituitary gland has an anterior lobe (adenohypophysis) and a posterior lobe (neurohypophysis).

Question 21

What hormones are secreted by the anterior pituitary?

Answer 21

The anterior pituitary secretes tropic hormones (ACTH, TSH, FSH, LH) and non-tropic hormones (growth hormone, prolactin, MSH).

Question 22

What hormones are secreted by the posterior pituitary?

Answer 22

The posterior pituitary stores and releases oxytocin and anti-diuretic hormone (ADH).

Question 23

What is the function of the pineal gland?

Answer 23

The pineal gland produces melatonin, which is involved in regulating sleep-wake cycles.

Question 24

What effect does more environmental light have on melatonin production?

Answer 24

More environmental light decreases melatonin production, contributing to wakefulness during the day.

Question 25

What is the function of the thyroid gland?

Answer 25

The thyroid gland regulates oxygen use, metabolic rate, cellular metabolism, growth, and development.

Question 26

How is thyroid hormone production regulated?

Answer 26

The hypothalamus releases Thyrotropin-Releasing Hormone (TRH), which stimulates the anterior pituitary to release Thyroid-Stimulating Hormone (TSH), leading to the release of thyroid hormones.

Question 27

What is the function of the parathyroid glands?

Answer 27

The parathyroid glands regulate blood calcium and phosphate levels.

Question 28

How does parathyroid hormone (PTH) affect blood calcium levels?

Answer 28

PTH increases blood calcium levels by stimulating osteoclasts, reabsorbing calcium in the kidneys, and activating vitamin D.

Question 29

Where are the adrenal glands located?

Answer 29

Paired glands located on the posterior body wall, superior to the kidneys.

Question 30

What regulates the secretion of hormones from the adrenal glands?

Answer 30

Hypothalamus, anterior pituitary, and sympathetic nervous system.

Question 31

What are the arterial supplies to the adrenal glands?

Answer 31

Superior arteries, middle artery, and inferior artery (3 suprarenal arteries: inferior phrenic artery, renal artery).

Question 32

How does venous drainage differ between the left and right adrenal glands?

Answer 32

The left adrenal gland drains into the left renal vein, while the right drains directly into the inferior vena cava.

Question 33

What are the anatomical and functional regions of the adrenal glands?

Answer 33

Cortex and medulla.

Question 34

What does the adrenal cortex secrete?

Answer 34

Corticoids (steroid hormones), essential for life.

Question 35

What are the three layers of the adrenal cortex?

Answer 35

Zona Glomerulosa, Zona Fasciculata, Zona Reticularis.

Question 36

What hormones are secreted by the Zona Glomerulosa?

Answer 36

Mineralocorticoids (e.g., aldosterone).

Question 37

What is the function of aldosterone?

Answer 37

Regulates mineral metabolism, increases sodium retention, decreases potassium, increases blood volume and pressure.

Question 38

What hormones are secreted by the Zona Fasciculata?

Answer 38

Glucocorticoids (e.g., cortisol).

Question 39

What is the function of cortisol?

Answer 39

Stress hormone involved in glucose metabolism, converts proteins and lipids to glucose, has anti-inflammatory properties.

Question 40

What hormones are secreted by the Zona Reticularis?

Answer 40

Gonadocorticoids (androgens).

Question 41

What is the function of gonadocorticoids?

Answer 41

Contributes to the development of male and female phenotypes.

Question 42

What is the function of the adrenal medulla?

Answer 42

Mediates the 'Fight or Flight' response.

Question 43

What hormones are secreted by the adrenal medulla?

Answer 43

Adrenaline (epinephrine) and noradrenaline (norepinephrine).

Question 44

How is the adrenal medulla regulated?

Answer 44

Controlled by the sympathetic nervous system.

Question 45

What is the mechanism of the short-term stress response?

Answer 45

Hypothalamus perceives threat, sympathetic nervous system activates, adrenaline released.

Question 46

What effects does the short-term stress response have?

Answer 46

Increases oxygen and glucose levels, heart rate, and blood pressure.

Question 47

What is the mechanism of the long-term stress response?

Answer 47

Hypothalamus releases corticotropin-releasing hormone, anterior pituitary releases ACTH, adrenal cortex releases aldosterone and cortisol.

Question 48

What effects does the long-term stress response have?

Answer 48

Increases glucose levels, blood pressure, and initially boosts immune response.

Question 49

What mediates the short-term stress response?

Answer 49

Sympathetic nervous system and adrenal medulla.

Question 50

What mediates the long-term stress response?

Answer 50

Adrenal cortex (Zona glomerulosa, Zona fasciculata).

Question 51

What hormones are involved in the parent stress response?

Answer 51

Cortisol and aldosterone from the adrenal cortex.

Question 52

What hormones are involved in the babysitter stress response?

Answer 52

Adrenaline (epinephrine) from the adrenal medulla.

Question 53

What is the endocrine function of the gonads?

Answer 53

Produce gametes and secrete sex hormones (estrogen, progesterone, testosterone).

Question 54

What regulates the gonads?

Answer 54

Hypothalamus and anterior pituitary (FSH and LH).

Question 55

What do the ovaries produce?

Answer 55

Follicles/ova and secrete estrogen and progesterone.

Question 56

What do the testes produce?

Answer 56

Sperm and testosterone.

Question 57

What is the function of Atrial Natriuretic Peptide (ANP)?

Answer 57

Reduces blood pressure and volume.

Question 58

What does leptin do?

Answer 58

Inhibits hunger and reduces fat storage.

Question 59

What hormone does the stomach produce to stimulate gastric juices?

Answer 59

Gastrin.

Question 60

What does secretin stimulate?

Answer 60

Pancreatic juice and bile secretion.

Question 61

What is the function of renin?

Answer 61

Raises blood pressure through vasoconstriction and aldosterone secretion.

Question 62

What does erythropoietin (EPO) stimulate?

Answer 62

Red blood cell production.

Question 63

What does Human Chorionic Gonadotropin (hCG) do?

Answer 63

Maintains corpus luteum after fertilization.

Question 64

How does the hypothalamus regulate the anterior pituitary gland?

Answer 64

The hypothalamus regulates the anterior pituitary through releasing and inhibiting hormones that travel via the hypophyseal portal system. These hormones are released into the bloodstream and influence the secretion of pituitary hormones.

Question 65

What are some of the releasing and inhibiting hormones secreted by the hypothalamus?

Answer 65

Examples include: Thyrotropin-releasing hormone (TRH): stimulates TSH release from the anterior pituitary. Corticotropin-releasing hormone (CRH): stimulates ACTH release from the anterior pituitary. Gonadotropin-releasing hormone (GnRH): stimulates LH and FSH release from the anterior pituitary. Growth hormone-releasing hormone (GHRH): stimulates GH release from the anterior pituitary. Somatostatin: inhibits GH and TSH release. Dopamine: inhibits prolactin release.

Question 66

How does the hypothalamus regulate the posterior pituitary gland?

Answer 66

The hypothalamus produces oxytocin and antidiuretic hormone (ADH), which are stored and released by the posterior pituitary. These hormones are transported along axons from the hypothalamus to the posterior pituitary for secretion into the bloodstream.

Question 67

What are the two main types of hormone receptors?

Answer 67

Cell surface receptors (for water-soluble hormones): These receptors are on the cell membrane and bind to hormones that cannot pass through the lipid bilayer, like peptide and protein hormones. Intracellular receptors (for lipid-soluble hormones): These receptors are located inside the cell (either in the cytoplasm or nucleus) and bind to hormones that can diffuse through the cell membrane, like steroid hormones and thyroid hormones.

Question 68

How do water-soluble hormones exert their effects on target cells?

Answer 68

Water-soluble hormones bind to cell surface receptors. This binding activates a signal transduction pathway that usually involves second messengers like cyclic AMP (cAMP) or calcium ions. These messengers trigger a cascade of intracellular events, ultimately resulting in a physiological response.

Question 69

How do lipid-soluble hormones exert their effects on target cells?

Answer 69

Lipid-soluble hormones diffuse through the cell membrane and bind to intracellular receptors in the cytoplasm or nucleus. The hormone-receptor complex then acts as a transcription factor, binding to DNA and regulating the expression of specific genes, leading to changes in protein synthesis.

Question 70

What is the hypothalamic-pituitary-adrenal (HPA) axis?

Answer 70

The HPA axis is the interaction between the hypothalamus, pituitary gland, and adrenal glands. The hypothalamus releases CRH, which stimulates the anterior pituitary to secrete ACTH. ACTH then stimulates the adrenal cortex to release cortisol, which regulates stress responses, metabolism, and immune function.

Question 71

How do lipid-soluble and water-soluble hormones differ in their effects on gene expression?

Answer 71

Lipid-soluble hormones: Bind to intracellular receptors and directly influence gene expression by acting as transcription factors. Water-soluble hormones: Bind to cell surface receptors, activating intracellular signaling pathways that typically do not directly alter gene expression but can influence cellular processes like enzyme activity.

Question 72

What is the function of hormone receptors on target cells?

Answer 72

Hormone receptors are proteins that bind to specific hormones, triggering a physiological response in the target cell. They ensure that only cells with the appropriate receptor can respond to a given hormone, allowing for specificity in hormonal signaling.