Physiology II - Sensory Systems and Homeostatic Mechanisms

Flashcards covering human physiology topics including vision, hearing, olfaction, gustation, urinary system, blood, digestion, endocrine system, and reproductive physiology.

Gaze Stabilization

Visual process to stabilize the eye when the head moves to bring a target into the fovea.

Vestibulo-ocular reflex (VOR)

Eye movement with a short latency period ($14\,ms$) that stabilizes images on the retina during fast head movements.

Crystalline Lens

A biconvex, transparent, avascular disc that refracts light and allows for precise focusing onto the retina.

Hyperopia

Farsightedness caused by an eyeball that is too short or a lens that is too weak, corrected with convex lenses.

Scotopic Vision

Night vision mediated by rods that detect dim light and perceive inputs only in grey tones.

Canal of Schlemm

The scleral venous sinus through which aqueous humor is reabsorbed into the venous blood.

Tonotopic Organization

The arrangement in the cochlea where different frequencies of sound activate specific hair cells along the basilar membrane.

Organ of Corti

The sense organ of hearing located on the basilar membrane containing hair cells and supporting cells.

Weber Test

A clinical hearing test that compares bone conduction on both sides using a vibrating tuning fork placed medially on the head.

Vomeronasal Organ (VNO)

A structure inside the nose that detects pheromones, subconsciously passed chemical signals between individuals.

Glomeruli (Olfactory)

Ball-like neural junctions in the olfactory bulb where receptors for a single scent component synapse with mitral cells.

Fungiform Papillae

Mushroom-shaped eminences on the tongue tip and sides containing taste buds, innervated by the Facial nerve (VII).

Umami

One of the five primary tastes, triggered by amino acids like glutamate and mediated by G-protein-coupled receptors.

Podocytes

Specialized epithelial cells in the inner layer of Bowman's capsule with foot processes that form filtration slits.

Renin-Angiotensin-Aldosterone System (RAAS)

A hormone system that regulates blood pressure and fluid balance by promoting sodium and water retention.

Glomerular Filtration Rate (GFR)

The rate of fluid transfer from glomerular capillaries to Bowman's capsule, normally averaging $125\,ml/min$.

Aquaporin-2 (AQP-2)

Water channels in the distal tubule and collecting ducts that are regulated by vasopressin (ADH).

Inulin

A foreign polysaccharide used to measure GFR because it is freely filtered but not reabsorbed or secreted.

Henderson-Hasselbalch Equation

$pH = pK + \log(\frac{[HCO_{3}^{-}]}{0.03 \times PCO_{2}})$ Used to calculate the pH of a buffer solution.

Anion Gap

Calculation used to identify metabolic acidosis causes: $[Na^{+}] - ([HCO_{3}^{-}] + [Cl^{-}])$; normal range is $8$ to $12\,mEq/L$.

Myelo-peroxidase

Enzyme in neutrophils and macrophages that catalyzes the reaction between $H_{2}O_{2}$ and chloride ions to kill bacteria.

Intrinsic Factor

A secretory product of parietal cells in the stomach necessary for the absorption of Vitamin $B_{12}$.

Enterohepatic Circulation

The recycling process where bile salts are reabsorbed in the terminal ileum and returned to the liver.

Chylomicrons

Large, lipoprotein-coated droplets of resynthesized triglycerides that enter central lacteals from intestinal cells.

Type 1 Diabetes (IDDM)

Condition caused by immune-mediated selective destruction of pancreatic $\beta$-cells, resulting in absolute insulin deficiency.

Leptin

A protein hormone produced by adipose tissue that provides long-term regulation of appetite by signaling fat stores to the brain.

Thyroglobulin (Tg)

A glycoprotein in the thyroid follicle colloid that serves as the scaffold for thyroid hormone synthesis.

Hypophysiotropic Hormones

Hypothalamic hormones that regulate the release or inhibition of anterior pituitary tropic hormones.

Interstitial Cells of Cajal

Electrical pacemakers in the GI tract that generate slow-wave potentials to regulate rhythmic contractions.

Corpus Luteum

A temporary endocrine structure in the ovary that secretes large amounts of progesterone to prepare the uterus for pregnancy.