Topic 1: Introduction, Organ Systems, Chemistry, and Biochemistry

Vocabulary practice flashcards covering introductory anatomy and physiology, structural levels of organisation, organ systems, directional terms and body planes, body cavities, homeostatic control mechanisms, receptors, and essential chemistry.

Anatomy

The study of the structure of body parts and their relationship to one another.

Physiology

The study of the function of body parts; how they work to carry out life-sustaining activities.

Gross (Macroscopic) Anatomy

The study of large, visible body structures such as specific regions, surface anatomy, and organ systems.

Microscopic Anatomy

The study of structures that cannot be seen with the naked eye, comprising cytology and histology.

Cytology

A branch of microscopic anatomy focusing on the study of body cells.

Histology

A branch of microscopic anatomy focusing on the study of tissues.

Levels of Structural Organisation

The hierarchical organisation of the human body: Chemical level (atoms and molecules) to Cellular level (cells made of molecules), Tissue level (similar cells), Organ level (different tissues), Organ system level (organs working closely together), to Organismal level (the complete human organism).

Median (Midsagittal) Plane

A vertical plane that runs longitudinally through the midline, dividing the body into equal right and left halves.

Frontal (Coronal) Plane

A vertical plane that divides the body into anterior (front) and posterior (back) parts.

Transverse Plane

A horizontal cross-sectional plane running from right to left that divides the body into superior (upper) and inferior (lower) parts.

Anatomical Body Planes

Standard sections used to view internal anatomy: (a) Median (midsagittal) plane, (b) Frontal (coronal) plane, and (c) Transverse plane.

Dorsal Body Cavity

A posterior cavity that protects the nervous system, subdivided into the cranial cavity (housing the brain) and the vertebral cavity (housing the spinal cord).

Ventral Body Cavity

An anterior body cavity partitioned by the diaphragm into the superior thoracic cavity and the inferior abdominopelvic cavity.

Thoracic Cavity

The superior subdivision of the ventral body cavity containing the pleural cavities (lungs), superior mediastinum, and the pericardial cavity enclosing the heart.

Abdominopelvic Cavity

The inferior subdivision of the ventral body cavity composed of the abdominal cavity (containing digestive viscera) and the pelvic cavity (containing urinary bladder, reproductive organs, and rectum).

Body Cavities

Internal spaces that enclose and protect organs: the Dorsal body cavity (cranial and vertebral cavities) and the Ventral body cavity (thoracic and abdominopelvic cavities).

Eleven Organ Systems

The eleven systems that comprise the human body: Nervous, Endocrine, Immune, Integumentary, Haematological, Musculoskeletal, Cardiovascular, Respiratory, Digestive, Urinary, and Reproductive systems.

Requirements for Life

Eight essential functional capabilities of the multicellular human organism: maintaining boundaries, movement, responsiveness, digestion, metabolism, excretion, reproduction, and growth.

Homeostasis

The maintenance of relatively stable internal conditions despite continuous changes in the external or internal environment.

Homeostatic Control Mechanism

The five-step regulatory loop: 1. Stimulus alters variable; 2. Receptor detects change; 3. Input is sent along afferent pathway to control center; 4. Output is sent along efferent pathway to effector; 5. Response feeds back to reduce stimulus effect and restore balance.

Receptor

A peripheral nerve ending specialised for responding to a particular stimulus (e.g., touch, sound waves) by generating an action potential, or a molecule that specifically binds other molecules (e.g., hormones, neurotransmitters) to transmit information.

Afferent Pathway

The communication pathway along which sensory input flows from the receptor to the control center.

Efferent Pathway

The communication pathway along which regulatory output travels from the control center to the effector organ or tissue.

Negative Feedback

The primary homeostatic feedback mechanism in the human body, where the output or response reduces or shuts off the original stimulus.

Positive Feedback

A feedback mechanism where the response enhances, amplifies, or accelerates the original stimulus in the same direction, often operating via a cascade effect.

Survival Needs

Five vital environmental and nutritional factors required for human survival: nutrients, oxygen, water, normal body temperature, and appropriate atmospheric pressure.

Element

A pure substance that cannot be broken down into simpler substances by ordinary chemical methods, composed of identical atoms that impart unique physical and chemical properties.

Molecule

A chemical particle formed when two or more atoms bond together (e.g., $O_2$).

Compound

A specific type of molecule composed of two or more different kinds of atoms bonded together (e.g., $H_2O$, $CO_2$).

Most Abundant Elements in the Human Body

The major chemical elements comprising human body mass: Oxygen ($61\%$), Carbon ($23\%$), Hydrogen ($10\%$), Nitrogen ($2.6\%$), Calcium ($1.4\%$), and Phosphorus ($1.1\%$).

Major Elements of the Human Body (CHON)

The four predominant elements: Carbon ($C$), Hydrogen ($H$), Oxygen ($O$), and Nitrogen ($N$).

Cations of the Human Body

Positively charged electrolytes (ions) essential for bodily function: Sodium ($Na^+$), Potassium ($K^+$), Hydrogen ($H^+$), Calcium ($Ca^{2+}$), and Magnesium ($Mg^{2+}$).

Anions of the Human Body

Negatively charged electrolytes (ions) essential for bodily function: Chloride ($Cl^-$), Hydroxide ($OH^-$), Bicarbonate ($HCO_3^-$), Sulfate ($SO_4^{2-}$), and Phosphate ($PO_4^{3-}$).

Glucose

A vital biological monosaccharide compound with the chemical formula $C_6H_{12}O_6$, containing $6$ carbon, $12$ hydrogen, and $6$ oxygen atoms.

Sodium Bicarbonate

A vital physiological compound with the chemical formula $NaHCO_3$, containing $1$ sodium, $1$ hydrogen, $1$ carbon, and $3$ oxygen atoms.