Ch. 9: The Endocrine System

Key Definitions

• Homeostasis: The maintenance of a stable internal environment within the body despite external changes.

• Endocrine glands: Ductless glands that secrete hormones directly into the bloodstream to regulate body functions.

• Hyposecretion: Insufficient production or release of a hormone by an endocrine gland.

• Hypersecretion: Excessive production or release of a hormone by an endocrine gland.

• Pheromones: Chemical signals released into the environment that affect the behavior or physiology of other individuals of the same species.

Hormones and Feedback Mechanisms

• Hormones: Chemical messengers produced by endocrine glands, transported by the bloodstream, and acting on target organs to regulate physiology and behavior.

• Negative feedback: A regulatory mechanism in which a stimulus causes an opposite output in order to maintain an ideal level of whatever is being regulated. For example, high blood glucose stimulates insulin release, which lowers blood glucose, reducing insulin secretion.

Hypothalamus

• Function: The hypothalamus links the nervous and endocrine systems by producing releasing and inhibiting hormones that control the pituitary gland. It also regulates body temperature, hunger, thirst, and circadian rhythms.

• Hormone Release Control: The hypothalamus controls the release of hormones from the anterior pituitary via releasing/inhibiting hormones and from the posterior pituitary via direct neural connections.

Major Hormones: Functions and Producing Organs

• ADH (Antidiuretic Hormone): Produced by the hypothalamus, released by the posterior pituitary; promotes water reabsorption in kidneys.

• GH (Growth Hormone): Produced by the anterior pituitary; stimulates growth and cell reproduction.

• MSH (Melanocyte-Stimulating Hormone): Produced by the anterior pituitary; influences skin pigmentation.

• Oxytocin (OT): Produced by the hypothalamus, released by the posterior pituitary; stimulates uterine contractions and milk ejection.

• ACTH (Adrenocorticotropic Hormone): Produced by the anterior pituitary; stimulates adrenal cortex to release cortisol.

• FSH (Follicle-Stimulating Hormone) & LH (Luteinizing Hormone): Produced by the anterior pituitary; regulate reproductive processes.

• Prolactin: Produced by the anterior pituitary; stimulates milk production.

• Melatonin: Produced by the pineal gland; regulates sleep-wake cycles.

• Calcitonin: Produced by the thyroid gland; lowers blood calcium levels.

• Thyroid Hormones (T3 and T4): Produced by the thyroid gland; regulate metabolism.

• Epinephrine (Adrenaline): Produced by the adrenal medulla; increases heart rate and energy in response to stress.

• Aldosterone: Produced by the adrenal cortex; regulates sodium and potassium balance.

• Cortisol: Produced by the adrenal cortex; regulates metabolism and stress response.

• Gonadotropins: FSH and LH, regulate gonadal function.

• Glucagon: Produced by the pancreas (alpha cells); raises blood glucose.

• Insulin: Produced by the pancreas (beta cells); lowers blood glucose.

• PTH (Parathyroid Hormone): Produced by the parathyroid glands; increases blood calcium.

• Androgens (e.g., Testosterone): Produced by testes; develop male characteristics.

• Estrogen & Progesterone: Produced by ovaries; regulate female reproductive system.

• Thymosin: Produced by the thymus; stimulates T-cell development.

• Growth factors, prostaglandins, leptin, ANH (Atrial Natriuretic Hormone): Various sources; regulate cell growth, inflammation, appetite, and blood pressure.

Table: Major Hormones and Their Producing Organs

Endocrine Disorders

• Hypothyroidism: Underactive thyroid; symptoms include fatigue, weight gain, cold intolerance.

• Cretinism: Congenital hypothyroidism in infants; leads to developmental delays.

• Myxedema: Severe hypothyroidism in adults; causes swelling and mental sluggishness.

• Hyperthyroidism: Overactive thyroid; symptoms include weight loss, heat intolerance, anxiety.

• Graves Disease: Autoimmune hyperthyroidism; may cause exophthalmos (eye bulging).

• Hyperparathyroidism/Hypoparathyroidism: Over/underproduction of PTH; affects calcium balance.

• Addison's Disease: Adrenal insufficiency; causes fatigue, low blood pressure, hyperpigmentation.

• Cushing's Syndrome: Excess cortisol; symptoms include obesity, moon face, muscle weakness.

• Diabetes Mellitus: Chronic high blood glucose due to insulin issues.

• Hypoglycemia/Hyperglycemia: Low/high blood glucose levels.

• Glycosuria: Glucose in urine; sign of diabetes.

• Polyuria, Polydipsia, Polyphagia: Excessive urination, thirst, and hunger, respectively; classic diabetes symptoms.

• Dwarfism, Gigantism, Acromegaly: Disorders of growth hormone affecting stature and bone growth.

• Goiter: Enlarged thyroid, often due to iodine deficiency.

• Diabetes Insipidus: Deficiency of ADH; causes excessive urination and thirst.

• Ketonuria: Ketones in urine; often seen in uncontrolled diabetes.

Ch. 10: Blood

Key Definitions

• Plasma: The liquid component of blood, containing water, proteins, nutrients, hormones, and waste products.

• Formed elements: The cellular components of blood: red blood cells (RBCs), white blood cells (WBCs), and platelets.

• Hematopoiesis: The process of blood cell formation, primarily occurring in the bone marrow.

• Stem cells: Undifferentiated cells capable of giving rise to various blood cell types.

• Phagocytosis: The process by which certain WBCs engulf and digest pathogens and debris.

• Agglutination: The clumping of cells, often due to antigen-antibody reactions (e.g., in blood typing).

Blood Cells: Characteristics and Functions

• Red Blood Cells (RBCs): Biconcave cells containing hemoglobin; transport oxygen and carbon dioxide.

• White Blood Cells (WBCs): Diverse group of immune cells; defend against infection and disease.

• Platelets: Cell fragments involved in blood clotting.

• Hemoglobin: Oxygen-carrying protein in RBCs; gives blood its red color.

Blood Clotting and Immunity

• Three Phases of Blood Clotting: Vascular spasm, platelet plug formation, coagulation (clotting cascade).

• Antigens and Antibodies: Antigens are surface markers on cells; antibodies are immune proteins that recognize and bind to specific antigens, important in blood typing and transfusion compatibility.

Ch. 11: The Cardiovascular System

Key Definitions

• Epicardium: Outer layer of the heart wall.

• Myocardium: Muscular middle layer of the heart wall; responsible for contraction.

• Endocardium: Inner lining of the heart chambers.

• Pericardial sac: Double-walled sac enclosing the heart.

• Systole: Phase of the heartbeat when the heart muscle contracts and pumps blood.

• Diastole: Phase when the heart muscle relaxes and fills with blood.

• Tunica intima, media, externa: Layers of blood vessel walls (inner, middle, outer, respectively).

• Cardiac cycle: Sequence of events in one heartbeat.

• Heart rate: Number of heartbeats per minute.

• Stroke volume: Amount of blood pumped by a ventricle per beat.

• Pulse: Rhythmic expansion of arteries with each heartbeat.

• Blood pressure: Force of blood against vessel walls.

• Diffusion: Movement of substances from high to low concentration.

• Osmotic pressure: Pressure exerted by solutes drawing water into the bloodstream.

Heart Structure and Function

• Heart: Muscular organ that pumps blood through the circulatory system.

• Pericardial fluid: Lubricates the heart within the pericardial sac.

• Atrium and Ventricle: Upper and lower chambers of the heart, respectively.

• Conduction system: Specialized cardiac tissue (e.g., SA node, AV node) that coordinates heartbeat.

• Bypass surgery: Surgical procedure to restore blood flow to the heart muscle.

• Cardioregulatory center: Brain region (medulla oblongata) that regulates heart rate and blood pressure.

Heart Valves and Circulation

• Bicuspid (Mitral) Valve: Between left atrium and left ventricle; prevents backflow.

• Tricuspid Valve: Between right atrium and right ventricle.

• Pulmonary Semilunar Valve: Between right ventricle and pulmonary artery.

• Aortic Semilunar Valve: Between left ventricle and aorta.

• SA Node (Sinoatrial Node): Pacemaker of the heart; initiates heartbeat.

• Systemic Circulation: Blood flow from heart to body and back.

• Pulmonary Circulation: Blood flow from heart to lungs and back.

• Arteries, Capillaries, Veins: Blood vessels carrying blood away from, to, and back to the heart, respectively.

• Atrial Systole/Diastole, Ventricular Systole/Diastole: Contraction/relaxation phases of heart chambers.

• Right/Left Side of Heart: Right side pumps deoxygenated blood to lungs; left side pumps oxygenated blood to body.

Capillary Exchange and Special Circulations

• Movement of Fluids in Capillaries: Filtration occurs at the arterial end (due to higher hydrostatic pressure), reabsorption at the venous end (due to higher osmotic pressure).

• Hepatic Portal System: Blood from digestive organs passes through the liver before returning to the heart.

• Brain Circulation: Includes the blood-brain barrier and circle of Willis for cerebral blood flow.

• Fetal Circulation: Features unique structures (foramen ovale, ductus arteriosus) to bypass nonfunctional fetal lungs.

Blood Pressure Regulation and Pathways

• High Blood Pressure Response: Vasodilation, decreased heart rate, increased urine output.

• Low Blood Pressure Response: Vasoconstriction, increased heart rate, fluid retention.

• Conducting System Pathway: SA node → AV node → Bundle of His → Bundle branches → Purkinje fibers.

• Blood Flow Pathway: Body → Right atrium → Right ventricle → Lungs → Left atrium → Left ventricle → Body.

Major Arteries and Veins

• General Locations: Aorta (main artery), vena cava (main vein), carotid arteries (neck), jugular veins (neck), femoral arteries/veins (thigh), etc.

• Lab Studies: Focus on identification and function of major vessels.

Cardiovascular Diseases

• Rheumatic Heart Disease: Heart valve damage from rheumatic fever.

• Endocarditis, Myocarditis, Pericarditis: Inflammation of heart layers.

• Atherosclerosis: Plaque buildup in arteries.

• Coronary Artery Disease: Reduced blood flow to heart muscle.

• Heart Failure: Inability of heart to pump effectively.

• Hypertension: High blood pressure.

• Congenital Heart Disease: Heart defects present at birth.

• Congestive Heart Failure: Fluid buildup due to poor heart function.

• Bradycardia/Tachycardia: Abnormally slow/fast heart rate.

• Aneurysm: Bulging of a blood vessel wall.

• Infarct/Myocardial Infarction: Tissue death due to lack of blood supply (heart attack).

• Arrhythmia: Irregular heartbeat.

• Hemorrhoids: Swollen veins in the rectum/anus.

• Phlebitis: Inflammation of a vein.

Additional info:

• Some terms and diseases are inferred based on standard Anatomy & Physiology curricula.

• For equations related to blood pressure:

• For cardiac output: