Human Anatomy and Physiology Study Flashcards

Comprehensive vocabulary flashcards covering the key structures, functions, pathways, and physiological mechanisms across the Cardiovascular, Nervous, Renal, Endocrine, Blood/Hemostasis, and Immune systems.

Superior Vena Cava (SVC)

A major vessel that returns deoxygenated blood from the head, neck, arms, and upper chest into the right atrium.

Inferior Vena Cava (IVC)

A major vessel that returns deoxygenated blood from the abdomen, pelvis, and legs into the right atrium.

Tricuspid Valve

A heart valve located between the right atrium and right ventricle that prevents backflow into the right atrium during ventricular contraction.

Pulmonary Artery

A blood vessel that carries deoxygenated blood from the right ventricle of the heart to the lungs.

Pulmonary Veins

Blood vessels that return oxygenated blood from the lungs into the left atrium of the heart.

Mitral (Bicuspid) Valve

A heart valve located between the left atrium and left ventricle that prevents backflow into the left atrium.

Left Ventricle

The strongest chamber of the heart that pumps oxygenated blood into the aorta for systemic circulation.

Systole

The contraction phase of the cardiac cycle during which blood is ejected from the heart chambers.

Diastole

The relaxation phase of the cardiac cycle during which the heart chambers fill with blood.

Cardiac Output (CO)

The volume of blood pumped by the heart each minute, calculated as $\text{CO} = \text{HR} \times \text{SV}$.

Total Peripheral Resistance (TPR)

The resistance blood encounters as it flows through the systemic circulation, created mainly by the arterioles.

Mean Arterial Pressure (MAP)

The average pressure in the arteries during one complete cardiac cycle, calculated as $\text{MAP} = \text{CO} \times \text{TPR}$.

Tunica Intima

The innermost layer of a blood vessel wall containing endothelium in direct contact with blood.

Tunica Media

The middle layer of a blood vessel wall composed of smooth muscle and elastic tissue that controls vessel diameter.

Tunica Adventitia

The outer connective-tissue layer of a blood vessel wall that anchors the vessel to surrounding tissue.

Resting Potential

The polarized state of a neuronal membrane at rest ($-70\text{ mV}$), maintained mainly by $\text{K}^+$ leak channels and the $\text{Na}^+/\text{K}^+$ ATPase.

Somatic Nervous System

A division of the peripheral nervous system responsible for voluntary control of skeletal muscle.

Autonomic Nervous System

A division of the peripheral nervous system responsible for involuntary control of organs and glands.

Acetylcholine (ACh)

The neurotransmitter released at the neuromuscular junction to stimulate muscle contraction and by parasympathetic and preganglionic autonomic neurons.

Blood-Brain Barrier (BBB)

A selective barrier formed by tight junctions between capillary endothelial cells that restricts substances from entering the CNS from the blood.

Cerebrum

The largest upper region of the brain that controls higher functions including thinking, memory, learning, language, sensory processing, emotions, and voluntary movement.

Cerebellum

A brain region located below the cerebrum at the back of the brain that coordinates balance, posture, muscle coordination, and fine motor movements.

Medulla Oblongata

A part of the brainstem regulating vital functions including breathing, heart rate, blood pressure, swallowing, coughing, sneezing, and vomiting.

Hypothalamus

A brain structure located below the thalamus that maintains homeostasis by regulating body temperature, hunger, thirst, sleep, hormone release, and autonomic functions.

Thalamus

A structure deep in the center of the brain that serves as the sensory relay station sending sensory information to the cerebral cortex.

Broca's Area

A region located within the frontal lobe that helps produce speech.

Wernicke's Area

A region located within the temporal lobe that helps understand spoken and written language.

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The major inhibitory neurotransmitter in the central nervous system that generally decreases neuronal excitability.

Glutamate

The major excitatory neurotransmitter in the central nervous system that plays a key role in learning, memory, and synaptic plasticity.

Renal Cortex

The outer layer of the kidney containing renal corpuscles and portions of the nephrons where blood filtration begins.

Renal Medulla

The inner region of the kidney containing loops of Henle and collecting ducts that establishes the osmotic gradient for concentrating urine.

Nephron

The functional unit of the kidney (~1 million per kidney) responsible for filtering blood and forming urine.

Glomerulus

A network of capillaries located in the renal cortex that filters blood under high pressure.

Descending Limb of Loop of Henle

A segment of the nephron in the renal medulla that is permeable to water and reabsorbs water by osmosis.

Ascending Limb of Loop of Henle

A segment of the nephron in the renal medulla that is impermeable to water and actively reabsorbs $\text{Na}^+$, $\text{K}^+$, and $\text{Cl}^-$.

Antidiuretic Hormone (ADH)

A hormone synthesized in the hypothalamus and released by the posterior pituitary that acts on collecting ducts to increase water reabsorption via aquaporin-2 channels.

Aldosterone

A hormone produced by the adrenal cortex that acts on the late distal nephron and collecting duct to increase $\text{Na}^+$ reabsorption and $\text{K}^+$ secretion.

Endocrine Signaling

A type of chemical signaling in which hormones travel through the bloodstream to reach distant target organs.

Paracrine Signaling

A type of chemical signaling in which chemical messengers act on nearby cells without traveling through systemic circulation.

Autocrine Signaling

A type of chemical signaling in which hormones act directly on the same cell that released them.

Cortisol

A hormone released by the adrenal cortex that regulates the stress response, glucose metabolism, inflammation, and blood pressure.

Insulin

A hormone secreted by beta ($\beta$) cells of the pancreatic islets of Langerhans that lowers blood glucose levels by promoting cellular glucose uptake and storage as glycogen.

Glucagon

A hormone secreted by alpha ($\text{α}$) cells of the pancreas that raises blood glucose levels by stimulating glycogenolysis and gluconeogenesis in the liver.

Hypothalamic-Pituitary-Thyroid (HPT) Axis

An endocrine pathway where TRH from the hypothalamus stimulates pituitary TSH, prompting the thyroid to release $\text{T}_3$ and $\text{T}_4$ to regulate metabolism.

Hypothalamic-Pituitary-Adrenal (HPA) Axis

An endocrine pathway where CRH from the hypothalamus stimulates pituitary ACTH, prompting the adrenal cortex to release cortisol during stress.

Erythrocytes

Red blood cells filled with hemoglobin that transport oxygen from the lungs to tissues and have an average lifespan of 120 days.

Hemoglobin

An iron-containing protein in RBCs consisting of four protein chains, four heme groups, and four $\text{Fe}^{2+}$ atoms that can bind up to four $\text{O}_2$ molecules.

Erythropoietin (EPO)

A hormone released by the kidneys during low blood oxygen levels that stimulates red blood cell production in the bone marrow.

von Willebrand factor (vWF)

A plasma protein that assists platelets in adhering to exposed subendothelial structures at vessel injury sites during primary hemostasis.

Thrombin (Factor IIa)

An active enzyme in the coagulation cascade that converts soluble fibrinogen (Factor I) into insoluble fibrin (Factor Ia).

Antithrombin

A protective regulatory protein that limits blood coagulation by inhibiting thrombin (Factor IIa) and Factor Xa.

Plasmin

An active enzyme responsible for fibrinolysis, breaking down fibrin strands to dissolve blood clots during tissue repair.

Innate Immunity

A rapid, non-specific immune defense mechanism present at birth that acts as the body's first line of defense without creating memory.

Adaptive Immunity

An antigen-specific immune response that develops after exposure, characterized by a slower initial response and long-term immunological memory.

B Cells

Lymphocytes originating in the bone marrow that recognize antigens, differentiate into antibody-producing plasma cells, and form memory B cells.

Helper T Cells

T lymphocytes that mature in the thymus and release cytokines to activate B cells and macrophages, coordinating overall adaptive immunity.

Cytotoxic T Cells

T lymphocytes that mature in the thymus and directly destroy virus-infected cells, cancer cells, and abnormal cells.

Antigen-Presenting Cells (APCs)

Specialized immune cells, such as dendritic cells, macrophages, and B cells, that capture and present antigens to T cells.

Interleukin-2 (IL-2)

A cytokine that functions as a key T-cell growth factor, stimulating the proliferation of T cells.