Blood, Hormones, Nervous & Renal Physiology – Comprehensive Vocabulary Deck

A vocabulary deck covering blood physiology, endocrine hormones, neurotransmitters, nervous system anatomy, cellular junctions, cardiovascular flow & conduction, and renal structure and function.

Hemoglobin (Hb)

Oxygen-carrying protein in red blood cells composed of 4 subunits, each with a heme iron that binds one O₂ (4 O₂ per Hb).

Myoglobin

Oxygen-binding protein in muscle and organ tissues that stores O₂ for rapid use.

Hematocrit

Laboratory test measuring the percentage of red blood cells in a blood sample.

Bohr Effect

Decrease in pH, increase in CO₂, or rise in temperature lowers hemoglobin’s affinity for O₂, promoting release to tissues.

Plasma

Non-cellular, water-like portion of blood containing proteins, ions, and clotting factors such as fibrinogen.

Red Blood Cell Lifespan

Erythrocytes circulate ~120 days before being degraded in the spleen.

Platelets

Cell fragments from megakaryocytes that initiate blood clotting and wound repair.

Megakaryocyte

Large bone-marrow cell that fragments into ~1,000 platelets.

Erythropoietin (EPO)

Hormone that stimulates red blood cell production in bone marrow.

Leukopoietin

Hormone that stimulates white blood cell production.

Thrombopoietin

Hormone that stimulates platelet production from megakaryocytes.

Anterior Pituitary

Endocrine gland releasing FSH, LH, ACTH, TSH, Prolactin, Endorphins, and Growth Hormone (mnemonic: FLAT PEG).

Follicle-Stimulating Hormone (FSH)

Stimulates gamete (egg & sperm) production in gonads.

Luteinizing Hormone (LH)

Triggers ovulation and stimulates sex steroid secretion (testosterone, estrogen).

Adrenocorticotropic Hormone (ACTH)

Promotes cortisol release from the adrenal cortex.

Thyroid-Stimulating Hormone (TSH)

Stimulates thyroid gland to produce T₃ and T₄.

Prolactin

Anterior pituitary hormone that promotes milk production in mammary glands.

Endorphins

Endogenous opioids that provide pain relief and euphoria.

Growth Hormone (GH)

Stimulates body growth, cell reproduction, and increases blood glucose usage.

Posterior Pituitary

Neuroendocrine tissue that releases ADH and oxytocin produced in the hypothalamus.

Antidiuretic Hormone (ADH, Vasopressin)

Increases water reabsorption in kidney collecting ducts; released with low BP or high plasma osmolarity.

Oxytocin

Peptide hormone causing uterine contractions, milk ejection, and social bonding (“love hormone”).

Adrenal Medulla

Inner adrenal region secreting epinephrine and norepinephrine for fight-or-flight responses.

Parathyroid Hormone (PTH)

Raises blood calcium by stimulating osteoclast bone resorption.

Calcitonin

Thyroid hormone that lowers blood calcium by inhibiting osteoclasts.

Adrenal Cortex

Outer adrenal layers producing aldosterone, cortisol, and androgens (salt, sugar, sex).

Aldosterone

Mineralocorticoid that increases Na⁺ reabsorption and blood pressure.

Cortisol

Glucocorticoid released during stress; raises blood glucose via gluconeogenesis.

Adrenal Androgens

Sex steroids produced by the adrenal cortex; supplementary source of testosterone/estrogens.

Human Chorionic Gonadotropin (hCG)

Placental hormone that maintains early pregnancy by sustaining the corpus luteum.

Testosterone

Leydig-cell androgen stimulated by LH; drives male sexual development and spermatogenesis.

Estrogen

Granulosa-cell steroid stimulated by FSH & LH; regulates female reproduction and secondary sex traits.

Peptide Hormone

Hydrophilic messenger that binds surface receptors; action is rapid and short-lived.

Steroid Hormone

Hydrophobic messenger derived from cholesterol; crosses membranes, acts slowly, and has lasting effects.

Amine Hormone

Tyrosine-derived hormones such as thyroid hormones, epinephrine, norepinephrine, and dopamine.

Dopamine

Catecholamine neurotransmitter for reward, movement, prolactin inhibition; imbalance linked to Parkinson’s and schizophrenia.

Acetylcholine (ACh)

Excitatory neurotransmitter critical for neuromuscular junction muscle contraction.

Glutamate

Primary excitatory CNS neurotransmitter; central to learning and memory; excess can cause excitotoxic stroke damage.

GABA

Major inhibitory neurotransmitter in the brain, reducing neuronal excitability.

Glycine

Inhibitory neurotransmitter of the spinal cord that decreases motor neuron excitability.

Serotonin

Modulatory neurotransmitter regulating mood, sleep, appetite, and gut motility.

Central Nervous System (CNS)

Brain and spinal cord; integrative and control centers.

Peripheral Nervous System (PNS)

Cranial and spinal nerves; divides into somatic (voluntary) and autonomic (involuntary) systems.

Autonomic Nervous System

Involuntary motor division comprising sympathetic (fight-or-flight) and parasympathetic (rest-and-digest) branches.

Frontal Lobe

Cerebral lobe for executive functions, voluntary movement, reasoning, and problem solving.

Parietal Lobe

Processes somatosensory information such as touch, pain, and pressure.

Occipital Lobe

Primary visual processing center of the brain.

Temporal Lobe

Handles auditory processing and language comprehension (Wernicke’s area).

Cerebellum

Brain region responsible for coordination and balance.

Limbic System

Emotional and memory center including hippocampus (memory) and amygdala (emotion).

Spinal Cord Dorsal Root

Posterior gray horn entry point for sensory (afferent) information.

Spinal Cord Ventral Root

Anterior gray horn exit point for motor (efferent) signals.

Input Zone

Neuronal dendrites & soma where graded EPSPs/IPSPs are generated.

Integrative Zone (Axon Hillock)

Neuron area that sums inputs and initiates an action potential if threshold is reached.

Conducting Zone

Axon and nodes of Ranvier that propagate the action potential.

Releasing Zone (Axon Terminal)

Region that releases neurotransmitters via Ca²⁺-dependent exocytosis.

Tight Junction

Epithelial seal preventing paracellular transport; forces molecules through cells (transcellular route).

Gap Junction

Intercellular channels allowing ions/small molecules to pass, enabling synchronized contraction in heart & smooth muscle.

Desmosome

Anchoring junction connecting cytoskeletal filaments of adjacent epithelial cells, resisting mechanical stress.

Hemidesmosome

Anchors basal surface of epithelial cell to basement membrane.

Working Cardiomyocyte

Contractile myocardial cell that shortens to generate force.

Sinoatrial (SA) Node

Heart pacemaker; autorhythmic cells that spontaneously depolarize to set heart rate.

Cardiac Blood Flow Path

RA → Tricuspid valve → RV → Pulmonary valve → Lungs → LA → Bicuspid valve → LV → Aortic valve → Aorta.

Systole

Phase of ventricular contraction; semilunar valves open and blood is ejected.

Diastole

Phase of ventricular relaxation; AV valves open and ventricles fill.

Hepatic Portal System

Blood from GI capillaries passes through liver via hepatic portal vein before systemic circulation.

Hypophyseal Portal System

Vascular link carrying hypothalamic hormones directly to the anterior pituitary.

Cardiac Conduction System

Sequence: SA node → Internodal/Bachmann fibers → AV node → Bundle of His → R/L bundle branches → Purkinje fibers.

Renal Cortex

Outer kidney layer housing most nephrons; performs filtration and reabsorption.

Renal Medulla

Inner kidney layer containing renal pyramids and loops of Henle.

Renal Pelvis

Funnel collecting urine into the ureter.

Nephron

Functional kidney unit filtering blood and forming urine; includes glomerulus, tubules, and collecting duct.

Glomerulus

Capillary tuft that filters plasma into Bowman’s capsule under pressure.

Bowman’s Capsule

Cup-like structure surrounding glomerulus that collects filtrate.

Proximal Convoluted Tubule (PCT)

Reabsorbs the majority of water, ions, and all glucose; filtrate ~300 mOsm.

Loop of Henle – Descending Limb

Permeable to water, impermeable to Na⁺; filtrate becomes concentrated.

Loop of Henle – Ascending Limb

Permeable to Na⁺ (actively reabsorbed), impermeable to water; filtrate becomes dilute.

Distal Convoluted Tubule (DCT)

Site of selective reabsorption/secretion; filtrate ~100 mOsm.

Collecting Duct

Final urine-modifying segment; water reabsorption controlled by ADH.

Filtration (Kidney)

Movement of plasma from glomerulus into Bowman’s capsule forming filtrate.

Reabsorption (Kidney)

Transport of substances from nephron back into the blood.

Secretion (Kidney)

Active transport of substances from blood into nephron filtrate.

Urea

Nitrogenous waste product of amino acid catabolism excreted in urine.

Creatinine

Waste product of muscle metabolism used to measure kidney function.

Effect of ADH on Urine

High ADH concentrates urine (up to ~1200 mOsm/L) and signals dehydration; low ADH dilutes urine.