Chapter 10 (exam 3)

Question 1

Endocrine vs exocrine glands—key structural and functional differences

Answer 1

Endocrine: ductless, richly vascular; secrete hormones into interstitial fluid → blood → distant targets. Exocrine: retain ducts; deliver non-hormonal products to body surface/lumen; act locally.

None

Question 2

Lipid-soluble hormone mechanism of action

Answer 2

Steroids & thyroid hormones diffuse through plasma membrane → bind intracellular receptors → hormone-receptor complex acts as transcription factor → alters mRNA synthesis → protein expression changes.

Slow-onset, long-lasting effects.

Question 3

Water-soluble hormone mechanism of action

Answer 3

Peptides, glycoproteins & catecholamines bind membrane receptors → activate second-messenger cascades → rapid enzyme activation, ion-channel modulation, or gene regulation.

Fast-onset, transient effects.

Question 4

One hormone, different effects—how?

Answer 4

Target-cell response depends on receptor type, receptor density, downstream second-messenger paths, and cooperative/antagonistic hormones.

Example: epinephrine constricts skin arterioles via α₁-receptors but dilates skeletal-muscle arterioles via β₂-receptors.

Question 5

Negative feedback definition + classic endocrine example

Answer 5

Output of a system inhibits the original stimulus to maintain homeostasis. Example: Rising plasma T₃/T₄ inhibits TRH and TSH release.

Stabilizes thyroid hormone levels.

Question 6

Positive feedback definition + endocrine example

Answer 6

Output amplifies the original stimulus until an external brake intervenes. Example: Oxytocin intensifies uterine contractions.

Loop ends once birth occurs.

Question 7

Antagonistic hormones + example

Answer 7

Hormones with opposite physiological effects; they create balanced control. Example: Insulin ↓ blood glucose; glucagon ↑ blood glucose.

Insulin promotes cellular uptake & glycogenesis; glucagon promotes glycogenolysis & gluconeogenesis.

Question 8

Synergistic hormones + example

Answer 8

Two or more hormones produce an enhanced effect together versus alone. Example: GH + thyroid hormone = maximal skeletal growth.

TH up-regulates GH receptors, GH drives protein synthesis.

Question 9

Structural link between hypothalamus and anterior pituitary

Answer 9

Hypothalamic neurosecretory cells release RH/IH into hypothalamo-hypophyseal portal system → primary capillary plexus → portal veins → secondary plexus in anterior pituitary.

Regulates trophic cell secretion.

Question 10

Structural link between hypothalamus and posterior pituitary

Answer 10

Hypothalamic magnocellular neurons extend axons through the infundibulum; terminals in posterior lobe store/release ADH & OT.

Releases into systemic blood.

Question 11

Define ‘tropic hormone’

Answer 11

Pituitary hormone that primarily regulates another endocrine gland’s growth or hormone output.

Examples include TSH, ACTH, FSH, LH.

Question 12

Growth Hormone (GH) profile

Answer 12

Stimulus = GHRH; inhibited by somatostatin. Targets = liver, bone, muscle, adipose. Actions = ↑ protein synthesis, ↑ lipolysis, ↓ glucose uptake. Hypo → children: pituitary dwarfism; adults: ↓ lean mass. Hyper → gigantism/acromegaly.

Gigantism occurs before epiphyseal closure, acromegaly after.

Question 13

Prolactin (PRL) profile

Answer 13

Stimulus = TRH, suckling; inhibited by dopamine. Targets = mammary glands. Actions = milk production, immune modulation. Hypo rare; hyper → galactorrhea, infertility.

Hyperprolactinemia inhibits GnRH.

Question 14

Thyroid-Stimulating Hormone (TSH) profile

Answer 14

Stimulus = TRH, ↓ T₃/T₄. Target = thyroid follicular cells. Action = ↑ iodine uptake, thyroglobulin iodination, T₃/T₄ release. Hyper → primary hyperthyroidism; hypo → secondary hypothyroidism.

TSH regulates thyroid function.

Question 15

Adrenocorticotropic Hormone (ACTH) profile

Answer 15

Stimulus = CRH, stress, early morning. Target = adrenal cortex. Action = ↑ cortisol synthesis. Hyper → Cushing’s disease; hypo → secondary adrenal insufficiency.

ACTH stimulates adrenal hormone production.

Question 16

Follicle-Stimulating Hormone (FSH) actions (male & female)

Answer 16

Females: stimulates granulosa cells → follicle maturation & estrogen. Males: stimulates Sertoli cells → spermatogenesis, ABP production.

FSH plays a critical role in reproductive function.

Question 17

Luteinizing Hormone (LH) actions (male & female)

Answer 17

Females: surge triggers ovulation, forms corpus luteum → progesterone. Males: stimulates Leydig cells → testosterone secretion.

LH is crucial for reproductive hormone regulation.

Question 18

Antidiuretic Hormone (ADH) / Vasopressin—role & disorders

Answer 18

Stimulus = ↑ plasma osmolarity, ↓ BP. Targets = kidney collecting ducts → ↑ water reabsorption; arterioles → vasoconstriction. Hyposecretion = central diabetes insipidus. Hypersecretion = SIADH.

ADH regulates fluid balance.

Question 19

Oxytocin (OT)—key functions (both sexes)

Answer 19

Females: uterine contraction (labor) & milk ejection. Males: possible role in ejaculation & pair-bonding.

Positive-feedback loop during parturition.

Question 20

Thyroid gland—location & overall function

Answer 20

Butterfly-shaped gland anterior to trachea; produces T₃/T₄ (regulates metabolism, growth, CNS development) and calcitonin.

Calcitonin lowers plasma Ca²⁺.

Question 21

T₃/T₄ synthesis and actions

Answer 21

Iodide uptake → oxidation → organification on thyroglobulin → coupling → endocytosis & proteolysis → release. Actions: ↑ Na⁺/K⁺-ATPase, ↑ O₂ consumption, ↑ metabolism.

Permissive for GH & catecholamines.

Question 22

Calcitonin—stimulus & role

Answer 22

Secreted by C-cells when plasma Ca²⁺ >10.5 mg/dL; inhibits osteoclast activity, weakly promotes renal Ca²⁺ excretion.

Minor regulator in adults, protective in growth/pregnancy.

Question 23

Parathyroid Hormone (PTH) physiology

Answer 23

Low Ca²⁺ sensed → ↑ PTH: stimulates osteoclasts, ↑ renal Ca²⁺ reabsorption, ↓ phosphate reabsorption, ↑ calcitriol production.

Increases gut Ca²⁺ absorption.

Question 24

Thyroid-related diseases (cretinism, simple goiter, Graves)

Answer 24

Cretinism: congenital hypothyroidism → stunted growth. Simple goiter: iodine deficiency → gland hypertrophy. Graves: autoimmune hyperthyroidism.

Includes symptoms like exophthalmos.

Question 25

Adrenal cortex zones & their hormones

Answer 25

Zona glomerulosa: mineralocorticoids (aldosterone). Zona fasciculata: glucocorticoids (cortisol). Zona reticularis: gonadocorticoids (DHEA). ## Footnote Each zone produces different classes of hormones.

Question 26

Adrenal medulla hormones & triggers

Answer 26

Chromaffin cells—80% epinephrine, 20% norepinephrine; release during acute stress via sympathetic activation. ## Footnote Increases HR, bronchodilation, glycogenolysis.

Question 27

Cortisol (glucocorticoid) major functions

Answer 27

↑ gluconeogenesis & blood glucose, ↑ protein catabolism, anti-inflammatory, immunosuppressive. ## Footnote Follows a circadian rhythm with AM peak.

Question 28

Aldosterone (mineralocorticoid) role

Answer 28

Acts on distal nephron → ↑ Na⁺ & water reabsorption, ↑ K⁺ excretion; stimulated by RAAS. ## Footnote Regulates blood pressure and electrolyte balance.

Question 29

Gonadocorticoids function

Answer 29

Adrenal androgens contribute to pubic/axillary hair & libido in females; negligible effect in adult males. ## Footnote Testicular androgens dominate in males.

Question 30

Addison’s disease pathophysiology

Answer 30

Primary adrenal cortical insufficiency → ↓ cortisol + ↓ aldosterone → weight loss, hypotension, hyperpigmentation. ## Footnote Symptoms include hyponatremia & hyperkalemia.

Question 31

Cushing’s syndrome causes & features

Answer 31

Chronic glucocorticoid excess; symptoms: central obesity, moon face, buffalo hump, muscle wasting. ## Footnote Causes include exogenous steroids and tumors.

Question 32

Acute vs long-term stress responses

Answer 32

Acute: catecholamines → ↑ HR, BP, glucose. Chronic: CRH → ACTH → ↑ cortisol & aldosterone → proteolysis, immunosuppression. ## Footnote Different mechanisms for stress adaptation.

Question 33

Pancreatic endocrine anatomy & hormones

Answer 33

Islets of Langerhans: β-cells (insulin), α-cells (glucagon), δ-cells (somatostatin). ## Footnote Each cell type has distinct hormonal functions.

Question 34

Insulin—stimulus, actions, antagonists

Answer 34

Stimulated by ↑ blood glucose/AA; promotes glucose uptake, glycogenesis, lipogenesis. Antagonized by glucagon, catecholamines. ## Footnote Insulin is key for lowering blood sugar.

Question 35

Glucagon—stimulus & actions

Answer 35

Stimulated by low blood glucose; promotes hepatic glycogenolysis, gluconeogenesis, lipolysis. ## Footnote Restores glucose levels.

Question 36

Thymus—hormone & role

Answer 36

Secretes thymosin & thymopoietin; promotes T-lymphocyte maturation & immune competence. ## Footnote Most active during childhood.

Question 37

Pineal gland—hormone & functions

Answer 37

Produces melatonin; regulates circadian rhythms, inhibits GnRH, acts as an antioxidant. ## Footnote Melatonin production is highest in darkness.

Question 38

Nitric Oxide (NO) functions

Answer 38

Diffuses to vascular smooth muscle → activates guanylate cyclase → vasodilation; also acts as a neurotransmitter. ## Footnote Key for penile erection and macrophage activity.

Question 39

Prostaglandins—general actions

Answer 39

Arachidonic acid derivatives; diverse roles: inflammation, pain, platelet aggregation, smooth muscle contraction/relaxation. ## Footnote Act paracrine/autocrine.

Question 40

Growth factors—definition & example

Answer 40

Local peptides that stimulate cell proliferation/differentiation. Example: EGF, PDGF, IGF-1. ## Footnote Critical for tissue repair and development.

Question 41

Diabetes Insipidus (central) – cause & hallmark signs

Answer 41

ADH deficiency → inability to concentrate urine → polyuria, polydipsia. ## Footnote Risk of dehydration & hypernatremia.

Question 42

Effect of alcohol on ADH and resulting symptoms

Answer 42

Ethanol inhibits ADH secretion → ↑ diuresis → dehydration, headache. ## Footnote Commonly experienced as a hangover.

Question 43

Gigantism vs Acromegaly distinction

Answer 43

Both = GH excess. Gigantism: before epiphyseal closure → proportional overgrowth. Acromegaly: after closure → enlarged hands, feet, jaw. ## Footnote Distinction based on age of onset.

Question 44

Simple feedback identification: Calcium homeostasis

Answer 44

↓ Ca²⁺ → PTH ↑; ↑ Ca²⁺ → calcitonin ↑; antagonistic loop maintains calcium levels. ## Footnote Keeps plasma Ca²⁺ between 8.5–10.5 mg/dL.

Question 45

Acute stress hormone trio ('fight-or-flight')

Answer 45

Epinephrine, norepinephrine, glucagon; mobilize glucose & redirect blood to vital organs. ## Footnote Essential for immediate stress response.

Question 46

Endocrine gland

Answer 46

Ductless hormone-secreting organ. ## Footnote Example: thyroid gland.

Question 47

Exocrine gland

Answer 47

Ducted, non-hormonal secretions. ## Footnote Example: sweat glands.

Question 48

Hormone

Answer 48

Blood-borne chemical messenger acting on distant targets at low concentrations. ## Footnote Critical for regulating physiological processes.

Question 49

Target cell

Answer 49

Cell possessing specific receptors for a hormone. ## Footnote Hormone action is dependent on receptor presence.

Question 50

First messenger

Answer 50

Extracellular hormone itself. ## Footnote Initiates signaling cascade.

Question 51

Second messenger

Answer 51

Intracellular mediator (e.g., cAMP) triggered by first messenger. ## Footnote Amplifies hormone signal within the cell.

Question 52

Neurosecretory cell

Answer 52

Hypothalamic neuron that releases hormones into blood. ## Footnote Critical for communication between the nervous and endocrine systems.

Question 53

Releasing hormone

Answer 53

Hypothalamic peptide stimulating anterior pituitary secretion. ## Footnote Example: TRH.

Question 54

Inhibiting hormone

Answer 54

Hypothalamic peptide suppressing anterior pituitary secretion. ## Footnote Example: dopamine.

Question 55

Pituitary

Answer 55

Master gland under hypothalamic control; anterior (adenohypophysis) & posterior (neurohypophysis) lobes. ## Footnote Plays a key role in hormone regulation.

Question 56

What is a second messenger?

Answer 56

Intracellular mediator (e.g., cAMP) triggered by first messenger ## Footnote Second messengers play a crucial role in cellular signaling pathways.

Question 57

Define neurosecretory cell.

Answer 57

Hypothalamic neuron that releases hormones into blood ## Footnote These cells are essential for the regulation of various bodily functions through hormone release.

Question 58

What is a releasing hormone?

Answer 58

Hypothalamic peptide stimulating anterior pituitary secretion ## Footnote Releasing hormones are critical for the regulation of many endocrine functions.

Question 59

Define inhibiting hormone.

Answer 59

Hypothalamic peptide suppressing anterior pituitary secretion ## Footnote Inhibiting hormones help maintain hormonal balance by preventing excess hormone secretion.

Question 60

What is the pituitary gland?

Answer 60

Master gland under hypothalamic control; anterior (adenohypophysis) & posterior (neurohypophysis) lobes ## Footnote The pituitary gland is crucial for regulating various endocrine functions in the body.

Question 61

What is a tropic hormone?

Answer 61

Hormone that stimulates another endocrine gland to grow and secrete hormones (e.g., TSH, ACTH) ## Footnote Tropic hormones play a vital role in the endocrine system by controlling the activity of other glands.

Question 62

What does growth hormone (GH) do?

Answer 62

Stimulates growth of bones, muscles, and tissues; promotes protein synthesis and fat metabolism ## Footnote GH is essential for normal physical development and metabolism.

Question 63

What is the function of prolactin (PRL)?

Answer 63

Promotes milk production in mammary glands ## Footnote Prolactin levels are crucial for breastfeeding and maternal health.

Question 64

What does thyroid-stimulating hormone (TSH) do?

Answer 64

Stimulates thyroid gland to release T₃ and T₄ ## Footnote TSH is key for regulating metabolism and energy levels.

Question 65

What is the role of adrenocorticotropic hormone (ACTH)?

Answer 65

Stimulates adrenal cortex to produce cortisol ## Footnote ACTH plays a significant role in the body's stress response.

Question 66

What does follicle-stimulating hormone (FSH) do?

Answer 66

Stimulates ovarian follicle growth and estrogen production in females; spermatogenesis in males ## Footnote FSH is important for reproductive health in both sexes.

Question 67

What is the function of luteinizing hormone (LH)?

Answer 67

Triggers ovulation and progesterone production in females; testosterone secretion in males ## Footnote LH is crucial for fertility and reproductive hormone regulation.

Question 68

What is antidiuretic hormone (ADH)?

Answer 68

Promotes water reabsorption in kidneys; secreted by posterior pituitary ## Footnote ADH is vital for maintaining body fluid balance.

Question 69

What does oxytocin do?

Answer 69

Stimulates uterine contractions during labor and milk ejection during nursing ## Footnote Oxytocin is often referred to as the 'love hormone' for its role in bonding and reproduction.

Question 70

What are thyroxine (T₄) and triiodothyronine (T₃)?

Answer 70

Thyroid hormones that regulate metabolism, growth, and development ## Footnote These hormones are essential for overall health and metabolic processes.

Question 71

What does calcitonin do?

Answer 71

Lowers blood calcium levels by inhibiting osteoclast activity ## Footnote Calcitonin helps regulate calcium homeostasis in the body.

Question 72

What is the function of parathyroid hormone (PTH)?

Answer 72

Increases blood calcium by stimulating osteoclasts and enhancing intestinal and renal absorption of calcium ## Footnote PTH is crucial for maintaining calcium balance in the body.

Question 73

What does cortisol do?

Answer 73

Stress hormone from adrenal cortex; increases blood glucose and suppresses inflammation ## Footnote Cortisol is essential for the body's response to stress.

Question 74

What is aldosterone?

Answer 74

Mineralocorticoid that promotes sodium retention and potassium excretion in kidneys ## Footnote Aldosterone plays a key role in blood pressure regulation and electrolyte balance.

Question 75

What is the role of epinephrine?

Answer 75

Adrenal medulla hormone that enhances 'fight-or-flight' response; increases heart rate and blood glucose ## Footnote Epinephrine is crucial for quick responses to stress or danger.

Question 76

What does norepinephrine do?

Answer 76

Hormone and neurotransmitter involved in vasoconstriction and blood pressure regulation ## Footnote Norepinephrine is essential for maintaining cardiovascular function.

Question 77

What is the function of glucagon?

Answer 77

Increases blood glucose by promoting glycogen breakdown and gluconeogenesis in the liver ## Footnote Glucagon is vital for energy regulation, especially during fasting.

Question 78

What does insulin do?

Answer 78

Lowers blood glucose by promoting cellular uptake and storage as glycogen or fat ## Footnote Insulin is critical for glucose metabolism and energy storage.

Question 79

What is thymosin?

Answer 79

Promotes T-cell development in the thymus ## Footnote Thymosin is important for immune system function.

Question 80

What does melatonin regulate?

Answer 80

Circadian rhythms and sleep cycles ## Footnote Melatonin is crucial for sleep regulation and overall well-being.

Question 81

What are prostaglandins?

Answer 81

Locally acting lipids involved in inflammation, pain, fever, and smooth muscle activity ## Footnote Prostaglandins have diverse roles in physiological processes.

Question 82

What is nitric oxide (NO)?

Answer 82

Vasodilator released by endothelial cells; also acts as a neurotransmitter and immune modulator ## Footnote NO plays a key role in regulating blood flow and immune response.

Question 83

Define negative feedback.

Answer 83

Control mechanism that reduces the output or activity of a system when levels are high ## Footnote Negative feedback is a fundamental principle in maintaining homeostasis.

Question 84

Define positive feedback.

Answer 84

Control mechanism that amplifies changes, such as oxytocin during childbirth ## Footnote Positive feedback is less common but crucial in certain physiological processes.

Question 85

What is diabetes insipidus?

Answer 85

Condition caused by ADH deficiency; results in excessive urination and thirst ## Footnote This condition is important to recognize for its impact on fluid balance.

Question 86

What is cretinism?

Answer 86

Congenital hypothyroidism; causes stunted growth and mental impairment in infants ## Footnote Early diagnosis and treatment are critical to prevent severe developmental issues.

Question 87

Define simple goiter.

Answer 87

Thyroid gland enlargement due to iodine deficiency ## Footnote Goiter can indicate underlying thyroid dysfunction and nutritional deficiencies.

Question 88

What is Graves’ disease?

Answer 88

Autoimmune hyperthyroidism; involves thyroid-stimulating immunoglobulins (TSI) ## Footnote This condition requires careful management due to its effects on metabolism.

Question 89

What is Addison’s disease?

Answer 89

Adrenal insufficiency leading to low cortisol and aldosterone; causes weakness, low BP, hyperpigmentation ## Footnote Addison's disease can be life-threatening without appropriate treatment.

Question 90

What is Cushing’s syndrome?

Answer 90

Excess cortisol; symptoms include moon face, central obesity, and muscle wasting ## Footnote This syndrome can have significant impacts on health and requires comprehensive management.

Question 91

What is SIADH?

Answer 91

Syndrome of inappropriate ADH secretion; causes water retention and hyponatremia ## Footnote SIADH can lead to serious electrolyte imbalances and needs careful monitoring.

Question 92

What is acromegaly?

Answer 92

Excess GH in adults; leads to enlarged hands, feet, jaw, and facial features ## Footnote Acromegaly can cause various complications and requires medical intervention.

Question 93

What is gigantism?

Answer 93

Excess GH in children before epiphyseal plates close; causes extreme height ## Footnote Early diagnosis and treatment are essential to manage growth disorders.

Question 94

What is central diabetes insipidus?

Answer 94

Inadequate secretion of ADH due to hypothalamic or pituitary damage ## Footnote This condition can significantly affect fluid balance and requires careful management.