Biomedicine: Human Sciences Lecture 1 - Cytology

Flashcards on basic cell biology, homeostasis, cell division, transport mechanisms, organelles, and tissue types from CNM Biomedicine Lecture 1.

Cytology

The field of study focused on cells, derived from the Greek 'cyto-' meaning cell or hollow vessel.

Anatomy

The study of the structure of the body and its parts.

Physiology

The study of how the body and its parts function.

Pathology

The study of diseases.

Metabolism

Chemical processes in the body that convert food into energy to be used for body functions.

Vital Force

The energy that animates the physical body, also known as Life Force or Qi.

Health

A state of abundant vitality representing the best possible physical and mental state.

Disease

A disruption in normal physiological functions of the body, leading to symptoms and impaired health.

Homeostasis

The condition of equilibrium or dynamic balance in the body's internal environment in response to external and internal changes.

Intracellular fluid

The fluid contained within cells, making up about two-thirds of the body's total water and supporting cellular processes.

Extracellular fluid

The fluid found outside cells, including blood, which transports nutrients, waste, and signaling molecules between cells.

Negative feedback

A homeostatic control system where the output reverses the input change to bring the body back to its normal state.

Positive feedback

A homeostatic control system where the output amplifies or reinforces a change to speed up a process.

Afferent pathway

A pathway that carries sensory signal input towards or arriving at the control centre in a homeostatic system.

Efferent pathway

A pathway that carries motor output away from or exiting the control centre to an effector in a homeostatic system.

Psychosomatic

Relating to how emotional or psychological disturbances in the mind affect the physical body.

The Cell Theory

A foundational concept stating that all living organisms are composed of cells, cells are the basic structural and functional units of life, all cells arise from pre-existing cells through division, and all energy flow of life occurs within cells.

Free radicals

Unstable, highly reactive molecules formed when oxygen-containing molecules lose an electron, causing them to steal electrons from nearby molecules and trigger oxidative damage.

Antioxidants

Molecules (such as vitamins C, E, and beta-carotene) that donate electrons to neutralise free radicals, protecting cells from damage.

Mutation

A change in the DNA sequence of a cell.

Cell membrane

The protective outer barrier of a cell composed of a phospholipid bilayer that controls what enters and exits the cell.

Phospholipid bilayer

A double-layered structural arrangement of the cell membrane consisting of water-loving phosphate heads and water-repelling fatty acid tails.

Transmembrane proteins

Proteins spanning across the cell membrane that assist with molecule transport, provide immunological identity, and function as receptors.

Nucleus

A spherical organelle containing the genetic code, acting as the control centre or brain of the cell.

Chromosomes

Tightly packed, condensed strands of DNA ($46$ individual or $23$ pairs in human somatic cells) carrying genetic instructions for the body.

Somatic cells

All non-reproductive body cells containing a full set of $46$ chromosomes ($23$ pairs).

Gametes

Reproductive sex cells (sperm and egg cells) that contain $23$ individual chromosomes.

Gene

A sub-section of DNA that acts as a hereditary unit containing instructions required to make a specific protein.

Mutagen

A mutation-causing agent such as radiation, harmful chemicals, viruses, or vaccines.

Ribosomes

Cellular organelles rich in RNA that serve as the primary sites of protein synthesis.

Transcription

The first phase of protein synthesis where a DNA gene sequence is copied into mRNA inside the nucleus.

Translation

The second phase of protein synthesis where a ribosome reads the mRNA code to assemble a protein from amino acids.

Cytoskeleton

A network of protein filaments extending through the cytosol that generates cell movement, provides physical support and shape, and separates chromosomes during division.

Mitochondria

The powerhouses of the cell that produce ATP through aerobic respiration using oxygen and glucose.

Adenosine Triphosphate (ATP)

The main energy currency molecule of the body produced within the mitochondria.

Rough endoplasmic reticulum

A network of flattened sacs covered with ribosomes on its surface, responsible for synthesising and transporting structural proteins like collagen.

Smooth endoplasmic reticulum

A ribosome-free membrane network involved in lipid synthesis (including steroid hormones) and detoxification of drugs and alcohol in liver cells.

Golgi apparatus

An organelle composed of flattened sacs that modifies, sorts, packages, and transports proteins received from the rough ER into vesicles for secretion.

Lysosomes

Cellular digestion vesicles containing up to $60$ enzymes that break down worn-out organelle parts, foreign materials, and cell waste.

Mitosis

A process of cell division in body cells involving one division cycle that produces two new genetically identical diploid daughter cells for growth and repair.

Meiosis

A process of cell division involving two division cycles that produces four genetically unique haploid gametes, each containing $23$ chromosomes.

Fertilisation

The fusion of a male gamete (sperm) and a female gamete (ovum) to form a single zygote.

Zygote

The cell resulting from fertilisation containing $46$ chromosomes arranged in $23$ pairs.

Passive transport

The movement of substances down a concentration gradient (from high to low concentration) across a cell membrane without requiring energy.

Diffusion

A type of passive transport involving the movement of small substances from an area of high concentration to an area of low concentration.

Osmosis

The passive movement of water molecules across a selectively permeable membrane.

Facilitated diffusion

The passive transport of larger substances down a concentration gradient across a cell membrane with the assistance of transmembrane proteins.

Active transport

The movement of substances up a concentration gradient (from low to high concentration) across a membrane requiring cellular energy (ATP).

Histology

The study of tissues.

Epithelial tissue

Tissue composed of tightly packed cells arranged in continuous sheets that covers body surfaces, lines internal cavities and organs, and forms glands.

Exocrine glands

Glands that secrete their products into ducts that carry secretions to body surfaces or internal cavities.

Endocrine glands

Ductless glands that release hormones directly into the surrounding interstitial fluid to diffuse into the bloodstream.

Connective tissue

The most diverse and abundant tissue type in the body, consisting of widely spaced cells in an extracellular matrix, functioning to support, bind, and protect.

Extracellular matrix

The non-cellular material surrounding connective tissue cells, consisting of ground substance and protein fibres.

Fibroblasts

Large, abundant connective tissue cells responsible for producing collagen and elastic protein fibres essential for repair and healing.

Adipocytes

Connective tissue cells specialised in storing fat to provide energy storage, insulation, and protection.

Collagen fibres

Thick, strong protein fibres arranged in parallel bundles that provide high tensile strength in bones, ligaments, and tendons.

Elastic fibres

Thin, stretchy protein fibres made of elastin that allow tissues in skin, blood vessels, and lungs to stretch and recoil to original shape.

Mucous membranes

Epithelial and connective tissue membranes lining hollow organs that open to the outside of the body, secreting mucus for protection, lubrication, and absorption.

Goblet cells

Specialised epithelial cells located within mucous membranes that produce and secrete mucus.

Serous membranes

Double-layered membranes lining body cavities that do not open to the exterior, secreting watery serous fluid to reduce friction between moving organs.

Synovial membranes

Membranes lining the cavities of freely movable joints that contain synoviocytes to produce lubricating and nourishing synovial fluid.