Human Anatomy and Physiology Vocabulary

Vocabulary flashcards covering core concepts in human anatomy and physiology, cell transport, tissue types, the central and peripheral nervous systems, action potentials, cranial nerves, and cardiovascular dynamics based on lecture notes.

Gross Anatomy

The study of large, visible structures of the body using techniques such as dissection and modern imaging.

Microscopic Anatomy

The study of microscopic body components, such as cells and tissues.

Physiology

The study of how body structures function, emphasizing chemical and physical processes that sustain life and maintain homeostasis.

Cell

The smallest independently functioning unit of life, enclosed by a flexible membrane containing cytoplasm and organelles.

Tissue

A group of similar cells working together to perform a specific function.

Organ

A distinct body structure composed of two or more tissue types, each performing one or more physiological roles.

Organ System

A group of multiple organs that collaborate to carry out major functions or meet the physiological needs of the body.

Organism

A living being that has a cellular structure and can independently perform all physiological functions necessary for life.

Homeostasis

The dynamic process by which the body constantly monitors and adjusts its internal conditions to maintain stability within a healthy range.

Set Point

The ideal value around which a physiological range fluctuates, such as $37^\circ\text{C}$ for human body temperature.

Negative Feedback

A homeostatic mechanism that reverses deviations from a set point to restore internal balance.

Positive Feedback

A physiological mechanism that amplifies changes in state rather than reversing them, such as during childbirth.

Passive Transport

The movement of substances down their concentration gradient without requiring cellular energy ($\text{ATP}$).

Active Transport

The movement of substances against their concentration gradient using cellular energy ($\text{ATP}$) and membrane protein pumps.

Simple Diffusion

The passive movement of small, non-polar molecules directly through the lipid bilayer.

Facilitated Diffusion

The passive movement of larger or polar molecules across a cell membrane via membrane proteins.

Osmosis

The diffusion of water across a semipermeable membrane toward areas with higher solute concentration.

Filtration

The movement of fluid and solutes driven by pressure gradients rather than concentration gradients.

Epithelial Tissue

Large sheets of cells covering exposed body surfaces, lining cavities and organs, and forming glandular tissue.

Endothelium

A specialized type of epithelium lining hollow organs and body cavities that do not connect to the exterior, such as blood vessels.

Skeletal Muscle Tissue

Voluntary muscle tissue attached to bones, characterized by long, cylindrical, striated fibers with multiple peripheral nuclei.

Cardiac Muscle Tissue

Involuntary muscle tissue forming the contractile walls of the heart, featuring short, branched, striated fibers with single central nuclei.

Smooth Muscle Tissue

Involuntary muscle tissue found in walls of major organs and passageways, composed of short, spindle-shaped, non-striated fibers with single nuclei.

Neuron

An electrically active cell responsible for computational processing and communication via electrical and chemical signals in nervous tissue.

Glial Cells

Supporting cells of nervous tissue that maintain homeostasis, produce myelin, supply nutrients, and remove waste.

Anatomical Position

Standardized reference posture with the body standing upright, feet shoulder-width apart and parallel, toes forward, and arms at sides with palms forward.

Prone

Describing a body orientation where the individual is lying face-down.

Supine

Describing a body orientation where the individual is lying face-up.

Sagittal Plane

An imaginary vertical plane dividing the body or an organ into right and left sides.

Frontal Plane

An imaginary vertical plane (also called coronal plane) dividing the body or an organ into anterior (front) and posterior (rear) portions.

Transverse Plane

An imaginary horizontal plane dividing the body or an organ into upper and lower portions, producing cross sections.

Dendrites

Highly branched neuronal processes that receive information from other neurons at synapses and direct it toward the cell body.

Axon

A single long fiber emerging from the neuron cell body that propagates nerve impulses to target cells.

Myelin

A lipid-rich insulating sheath surrounding axons, created by oligodendrocytes in the CNS and Schwann cells in the PNS.

Node of Ranvier

A gap in the myelin covering along an axon that facilitates electrical signal transmission.

Unipolar Neuron

A sensory neuron with a single process extending from the cell body that quickly splits into two branches.

Bipolar Neuron

A rare neuron with two distinct processes—one axon and one dendrite—emerging from opposite ends of the cell body.

Multipolar Neuron

The most common neuron type in the nervous system, featuring one axon and two or more dendrites.

Astrocyte

A star-shaped CNS glial cell that interacts with neurons and blood vessels to maintain the blood-brain barrier.

Ependymal Cell

A specialized CNS glial cell lining brain ventricles that filters blood plasma at the choroid plexus to produce cerebrospinal fluid ($\text{CSF}$).

Blood-Brain Barrier

A physiological barrier formed by astrocytes restricting circulating blood substances from freely entering the central nervous system.

Action Potential

A change in electrical charge across an excitable cell membrane driven by regulated ion movement.

Resting Membrane Potential

The steady-state voltage across an unstimulated neuron membrane, typically measuring $-70\,\text{mV}$.

Depolarisation

The initial action potential phase where voltage-gated $\text{Na}^+$ channels open, allowing rapid influx of sodium that makes the membrane potential less negative.

Repolarisation

The action potential phase where voltage-gated $\text{K}^+$ channels open and potassium exits the cell, shifting membrane voltage back toward $-70\,\text{mV}$.

Hyperpolarisation

A brief overshoot during repolarization where membrane voltage drops below $-70\,\text{mV}$ because delayed $\text{K}^+$ channels remain open longer than necessary.

Synapse

A specialized junction where electrical or chemical information is transferred between a presynaptic neuron and a postsynaptic target cell.

Grey Matter

Regions within nervous system structures predominantly containing cell bodies and dendrites.

White Matter

Regions within nervous system structures composed largely of myelinated axons.

Brainstem

Brain region comprising the midbrain, pons, and medulla oblongata that connects the brain to the spinal cord and regulates vital cardiovascular and respiratory functions.

Cerebrum

The largest mass of the brain, split into right and left cerebral hemispheres, responsible for higher cognitive functions and sensory integration.

Cerebellum

Structure located posterior to the brainstem that compares motor commands from the cerebrum with sensory feedback from the periphery.

Meninges

Three connective tissue protective membranes (dura mater, arachnoid mater, and pia mater) covering the central nervous system.

Sympathetic Nervous System

Thoracolumbar division of the autonomic nervous system responsible for 'fight or flight' homeostatic responses.

Parasympathetic Nervous System

Craniosacral division of the autonomic nervous system responsible for 'rest and digest' homeostatic functions.

Reflex Arc

The pathway followed by nerve impulses during an automatic reflex action, including receptor, sensory neuron, integration centre, motor neuron, and effector.

Vagus Nerve

Tenth cranial nerve (CN X); the longest cranial nerve, carrying sensory, motor, and parasympathetic fibers to thoracic and abdominal organs.

Erythrocyte

Anucleate red blood cell lacking organelles that transports oxygen from the lungs to tissues and carbon dioxide back to the lungs.

Leukocyte

Nucleated white blood cell containing organelles that defends the body against pathogens, mutated cells, and cellular debris.

Neutrophil

Most abundant leukocyte ($50\text{--}70\%$ of total WBCs), acting as a rapid phagocyte with a preference for bacterial infections.

Eosinophil

Granular leukocyte ($2\text{--}4\%$ of total WBCs) containing antihistamines, active against parasitic worm infestations and allergic reactions.

Basophil

Least common leukocyte ($<1\%$ of total WBCs) that releases histamine to intensify inflammation and heparin to oppose blood clotting.

Lymphocyte

Leukocyte ($20\text{--}30\%$ of total WBCs) originating from lymphoid stem cells, comprising B-cells, T-cells, and NK cells essential for immune response.

Monocyte

Agranular leukocyte ($2\text{--}8\%$ of total WBCs) that leaves circulation to differentiate into a macrophage and phagocytize pathogens and debris.

Thrombocyte

A blood platelet, which is a tiny cytoplasmic fragment released from a megakaryocyte in bone marrow to assist in blood clotting.

Albumin

The most abundant plasma protein ($60\%$ of total plasma proteins), produced by the liver, maintaining blood colloidal osmotic pressure and transporting lipids.

Haemostasis

The positive-feedback process stopping bleeding when a blood vessel is damaged, involving vascular spasm, platelet plug formation, and coagulation.

Coagulation

The formation of a stable blood clot via a cascade where thrombin converts soluble fibrinogen into an insoluble fibrin mesh.

Pericardium

Tough membrane surrounding and enclosing the heart within the mediastinum.

Pulmonary Circuit

Circulatory pathway that transports deoxygenated blood to the lungs for gas exchange and returns oxygenated blood to the left atrium.

Systemic Circuit

Circulatory pathway that transports oxygenated blood from the left ventricle to body tissues and returns deoxygenated blood to the right atrium.