A&P 2. Exam 1 study guide

Hormone function regarding metabolism?

Regulates metabolic rate and energy balance.

Hormone function regarding growth?

Controls growth and development.

Hormone function regarding reproduction?

Regulates the operation of reproductive systems.

Hormone function regarding fluid balance?

Regulates chemical composition and volume of extracellular fluid.

What is down-regulation?

A decrease in target-cell receptors due to chronically high hormone levels.

Down-regulation effect on sensitivity?

Makes the target cell less sensitive to a hormone.

What is up-regulation?

An increase in target-cell receptors due to low hormone levels.

Up-regulation effect on sensitivity?

Makes the target cell more sensitive to a hormone.

Primary raw material needed to produce steroid hormones?

Cholesterol.

Primary raw material needed to produce eicosanoid hormones?

Arachidonic acid (a 20-carbon fatty acid).

Structural building blocks needed to produce peptide hormones?

Amino acids.

Permissive effect (definition)?

A hormone requires simultaneous or recent exposure to a second hormone to function.

Synergistic effect (definition)?

Two hormones acting together produce a greater effect than the sum of their individual effects.

Antagonistic effect (definition)?

One hormone completely opposes the actions of another hormone.

Circulating hormones (pathway)?

Pass from secretory cells into interstitial fluid, then enter the bloodstream to travel to distant targets.

Local hormones (pathway)?

Act on neighboring cells or the same cell without entering the bloodstream.

Paracrine vs. Autocrine?

Paracrines act on neighboring cells; autocrines act on the exact cell that secreted them.

What triggers hormone release from the anterior pituitary gland?

Releasing hormones delivered from the hypothalamus.

Transport pathway from hypothalamus to anterior pituitary?

The hypophyseal portal system.

Somatotropin (GH) origin?

Anterior pituitary.

Somatotropin (GH) primary effect?

Stimulates secretion of insulin-like growth factors (IGFs) to accelerate tissue growth.

Prolactin (PRL) origin?

Anterior pituitary.

Prolactin (PRL) primary effect?

Initiates and maintains milk production by mammary glands.

Thyrotropin (TSH) origin?

Anterior pituitary.

Thyrotropin (TSH) primary effect?

Stimulates synthesis and secretion of thyroid hormones ($T_3$ and $T_4$).

Luteinizing Hormone (LH) origin?

Anterior pituitary.

LH primary effect in females?

Triggers ovulation and stimulates progesterone secretion.

LH primary effect in males?

Stimulates testes to secrete testosterone.

Adrenocorticotropic Hormone (ACTH) origin?

Anterior pituitary.

Adrenocorticotropic Hormone (ACTH) primary effect?

Stimulates the adrenal cortex to secrete glucocorticoids (mainly cortisol).

Melanocyte-Stimulating Hormone (MSH) origin?

Anterior pituitary.

Melanocyte-Stimulating Hormone (MSH) primary effect?

Can influence brain activity; causes skin darkening when present in excess.

Insulin-like Growth Factors (IGFs) origin?

Liver, skeletal muscle, cartilage, and bone.

Insulin-like Growth Factors (IGFs) primary effect?

Increase protein synthesis and accelerate cell division/growth.

Oxytocin site of synthesis?

Hypothalamus.

Oxytocin site of storage & release?

Posterior pituitary.

Oxytocin uterine effect?

Enhances smooth muscle contraction during labor.

Oxytocin mammary effect?

Stimulates milk ejection ('let-down') in response to suckling.

Antidiuretic Hormone (ADH) site of synthesis?

Hypothalamus.

Antidiuretic Hormone (ADH) site of storage & release?

Posterior pituitary.

ADH renal effect?

Causes kidneys to retain more water, decreasing urine volume.

ADH vascular effect?

Constricts arterioles to raise blood pressure (vasopressin).

Calcitonin origin?

Parafollicular cells (C cells) of the thyroid gland.

Calcitonin primary effect?

Lowers blood calcium levels by inhibiting osteoclasts.

Parathyroid Hormone (PTH) origin?

Chief cells of the parathyroid glands.

Parathyroid Hormone (PTH) primary effect?

Raises blood calcium levels by stimulating osteoclasts.

Insulin origin?

Beta cells of pancreatic islets.

Insulin primary effect?

Lowers blood glucose by accelerating glucose uptake into cells.

Glucagon origin?

Alpha cells of pancreatic islets.

Glucagon primary effect?

Raises blood glucose by accelerating glycogenolysis and gluconeogenesis in the liver.

Thyroid hormones ($T_3$ and $T_4$) origin?

Follicular cells of the thyroid gland.

Thyroid hormones ($T_3$ and $T_4$) primary effect?

Increase basal metabolic rate (BMR) and cellular metabolism.

Human Chorionic Gonadotropin (hCG) origin?

Placenta.

Human Chorionic Gonadotropin (hCG) primary effect?

Stimulates the corpus luteum to maintain progesterone production during early pregnancy.

Leptin origin?

Adipose tissue.

Leptin primary effect?

Suppresses appetite and regulates energy balance.

What hormone is stored in large quantities for approx 100 days?

Thyroid hormones ($T_3$ and $T_4$, stored as thyroglobulin).

Long-term stress response phase?

The resistance reaction.

Primary glucocorticoid released during long-term stress?

Cortisol.

Effect of cortisol during long-term stress?

Lipolysis, gluconeogenesis, protein catabolism, and immune suppression.

Primary mineralocorticoid released during long-term stress?

Aldosterone (causes $Na^+$ and water retention).

Aging effect on Growth Hormone (GH)?

Decreases secretion, leading to muscle atrophy.

Aging effect on thyroid hormones?

Decreases $T_3$/$T_4$ output, lowering metabolic rate.

Aging effect on PTH?

Levels rise, contributing to osteoporosis.

Cause of Acromegaly?

Hypersecretion of Growth Hormone (GH) during adulthood.

Key anatomical sign of Acromegaly?

Enlargement/thickening of bones in the hands, feet, and face.

Cause of Graves’ disease?

Autoimmune hyperthyroidism (antibodies mimic TSH).

Key clinical sign of Graves' disease?

Exophthalmos (protruding eyes) and rapid weight loss.

Cause of Myxedema?

Hypothyroidism during adulthood.

Key clinical sign of Myxedema?

Facial puffiness, edema, slow heart rate, and cold intolerance.

Cause of Cushing’s Syndrome?

Hypersecretion of cortisol by the adrenal cortex.

Key clinical signs of Cushing's Syndrome?

 "Moon face," "buffalo hump," and abdominal stretch marks.

What is Hirsutism?

Excessive body hair growth in females due to excess androgen production.

What is Gynecomastia?

Development of breast tissue in males due to an estrogen/androgen imbalance.

Hormones secreted due to a chemical change in blood (Humoral)?

Insulin, glucagon, PTH, and calcitonin.

Hormones produced by the ovaries?

Estrogens, progesterone, inhibin, and relaxin.

Blood function: Transportation?

Moves $O_2$, $CO_2$, nutrients, hormones, heat, and wastes.

Blood function: Regulation?

Maintains homeostasis of pH, body temperature, and cell water content.

Blood function: Protection?

Uses clotting to prevent blood loss and WBCs/antibodies to fight infections.

Normal temperature of blood?

38°C (100.4°F).

Normal pH range of blood?

7.35 to 7.45.

What is hematocrit?

The percentage of total blood volume occupied by red blood cells.

Percentage of water in blood plasma?

About 91.5%.

Most abundant plasma protein?

Albumin.

Primary role of Albumin?

Maintains blood colloid osmotic pressure.

Primary role of Globulins?

Immunoglobulins attack pathogens; alpha/beta types transport lipids.

Primary role of Fibrinogen?

Functions as a key molecule in blood clotting.

What is hemopoiesis?

The process by which the formed elements of blood develop.

Primary site of adult hemopoiesis?

Red bone marrow.

What are proerythroblasts?

Earliest committed red blood cell precursor stem cells.

What hormone stimulates RBC proliferation?

Erythropoietin (EPO).

What is ferritin?

An intracellular protein that safely stores iron in cells.

What are reticulocytes?

Immature red blood cells that have just ejected their nucleus.

High reticulocyte count meaning?

Indicates a rapid, high rate of RBC production.

What do platelets develop from?

Megakaryoblasts (which fragment from megakaryocytes).

Primary role of platelets?

Form a platelet plug to stop blood loss during hemostasis.

What hormone stimulates platelet production?

Thrombopoietin (TPO).

Myeloblasts develop into $\rightarrow$ ?

Granular leukocytes (Neutrophils, Eosinophils, Basophils).

Megakaryoblasts develop into $\rightarrow$ ?

Megakaryocytes (which shatter into Platelets).

Reticulocytes develop into $\rightarrow$ ?

Mature Erythrocytes (RBCs).