Human Anatomy, Physiology, and Neuroscience Comprehensive Review

Vocabulary flashcards covering human anatomy and physiology, including the respiratory system, immune defenses, gastrointestinal processing, endocrine regulation, and foundational cellular and cognitive neuroscience.

Upper Airway

The respiratory passage responsible for transporting air between the external environment and the lungs, consisting of the nasal cavity, oral cavity, pharynx, larynx, trachea, and bronchial tree.

Alveoli

Microscopic, thin-walled air sacs located at the terminus of the bronchial tree where respiratory gas exchange of oxygen ($O_2$) and carbon dioxide ($CO_2$) occurs between air and blood.

Inspiration

The active phase of ventilation in which expansion of the chest wall and contraction of the diaphragm cause air to be drawn into the lungs, analogous to the expansion of an air bellow.

Innate Immunity

Non-specific host defenses present at birth that provide an immediate early-warning barrier against all microbes without requiring specific pathogen recognition; includes physical barriers like the epidermis and mucous membranes, as well as phagocytes, natural killer cells, and inflammation.

Adaptive Immunity

Specific defense mechanisms mediated by T lymphocytes and B lymphocytes that recognize, adjust to, and eliminate specific invading pathogens once innate barriers are breached.

Mucosa-Associated Lymphoid Tissue (MALT)

Aggregates of lymphoid tissue found within the mucosal linings of major physiological tracts, including the respiratory, digestive, and urogenital systems.

Peristalsis

Coordinated involuntary muscular contractions of the hollow organs of the gastrointestinal tract, where muscles behind food contract while muscles ahead relax to propel contents forward.

Chyme

The semifluid mass of partially digested food mixed with gastric acid and digestive enzymes that is slowly emptied from the stomach into the small intestine.

Enteric Nervous System (ENS)

An autonomous network of nerves embedded in the walls of the gastrointestinal tract that regulates local muscle contractions, transit speed, and digestive juice secretions in response to wall stretch.

Bile

A digestive fluid produced by the liver, stored in the gallbladder, and delivered via ducts into the small intestine to emulsify and break down fats and aid vitamin absorption.

Growth Hormone (GH)

An anterior pituitary protein hormone that stimulates organ growth and mobilizes food molecules to increase blood glucose concentrations; hypersecretion results in gigantism and acromegaly.

Antidiuretic Hormone (ADH)

A peptide hormone synthesized in the hypothalamus and released by the posterior pituitary that stimulates water retention by the kidneys; hyposecretion leads to diabetes insipidus.

Calcitonin

A polypeptide hormone secreted by the thyroid gland that inhibits bone resorption and lowers blood calcium concentrations.

Parathyroid Hormone (PTH)

A polypeptide hormone secreted by the parathyroid glands that stimulates bone breakdown to elevate blood calcium concentrations.

Aldosterone

A steroid mineralocorticoid secreted by the adrenal cortex that regulates fluid and electrolyte homeostasis by promoting renal sodium and water retention.

Glucagon

A polypeptide hormone synthesized by the alpha cells of the pancreatic islets that stimulates hepatic glycogenolysis to elevate blood glucose concentrations.

Action Potential

A rapid, all-or-nothing electrical pulse generated across a neuronal membrane when depolarization opens voltage-gated $Na^+$ channels, shifting the transmembrane potential from approximately $-70\,\text{mV}$ to $+30\,\text{mV}$, followed by repolarization via $K^+$ outflow.

Oligodendrocytes

Specialized glial cells of the central nervous system that wrap multiple neuronal axons in fatty myelin sheaths to enhance action potential conduction speed.

Saltatory Conduction

The rapid jumping of action potentials from one node of Ranvier to the next along a myelinated axon, accelerating signal velocity up to $100\,\text{m/s}$.

Fovea

The central pit of the retina where incoming light is focused, densely packed exclusively with red and green cone photoreceptors to produce high visual acuity.

Nociceptors

Peripheral sensory nerve endings specialized to detect tissue-damaging thermal ($> 46^\circ\text{C}$), mechanical, or chemical stimuli and initiate the transmission of pain signals to the spinal cord.

Motor Unit

A fundamental functional motor entity consisting of a single alpha motor neuron in the spinal cord or brainstem and all of the skeletal muscle fibers it innervates.

Suprachiasmatic Nucleus

A bilateral group of nerve cells in the hypothalamus that functions as the primary master circadian clock by expressing clock proteins in a self-sustaining cycle of approximately $24\,\text{hours}$.

Broca's Area

A specialized region situated in the left frontal lobe critical for speech production; damage causes nonfluent aphasia characterized by halting, effortful speech output.

Long-Term Potentiation (LTP)

A long-lasting increase in synaptic strength following high-frequency stimulation, initiated by the expulsion of $Mg^{2+}$ blocks from NMDA receptors, influx of $Ca^{2+}$, and the subsequent recruitment or phosphorylation of postsynaptic AMPA receptors.

Dendritic Spines

Microscopic, bulbous protrusions extending from neuronal dendrites that contain postsynaptic receptor machinery and serve as the primary structural sites for receiving excitatory synaptic inputs.

Hypothalamic-Pituitary-Adrenal (HPA) Axis

A neuroendocrine stress-response cascade in which the hypothalamus secretes corticotropin-releasing hormone (CRH), inducing anterior pituitary secretion of ACTH, which stimulates the adrenal cortex to release cortisol.

Cytokines

A diverse class of protein signaling molecules (including interleukins, interferons, and tumor necrosis factors) produced by immune cells and damaged tissues to regulate inflammation and relay signals to the central nervous system.

Magnocellular System

A visual stream consisting of large retinal ganglion cells and geniculate neurons that rapidly tracks motion, depth, and flicker, whose developmental disruption is implicated in some forms of developmental dyslexia.

Neuroethics

An interdisciplinary field exploring the moral, legal, and social implications of neuroscientific discoveries, technologies, cognitive enhancements, and treatments on society.