Lecture Notes: Anatomy, Histology, Cells, and Bones

Vocabulary flashcards covering key terms from the lecture notes.

Anatomy

The study of the structural organization of the human body from cells to tissues to organs and organ systems.

Physiology

The study of the functions and activities of the body's structures and systems.

Homeostasis

Maintenance of a stable internal environment, often via negative feedback systems.

Gradient

A difference in a quantity (e.g., concentration, pressure, electrical potential) across space that drives diffusion or flow.

Electrochemical gradient

A gradient combining electrical and chemical (concentration) differences that guides transport of ions.

Covalent bond

A strong bond formed by sharing electrons between atoms, creating a molecule.

Ionic bond

A bond formed between oppositely charged ions; strong in vacuum but weakened in water.

Mitochondria

Organelle with its own DNA; site of aerobic respiration and protein synthesis within the organelle.

Nucleus

Organelle containing most of the cell’s DNA; site of DNA replication and transcription.

DNA replication

Process of copying the DNA molecule prior to cell division.

Transcription

Synthesis of RNA from a DNA template.

Translation

Synthesis of proteins from mRNA at ribosomes.

Nucleotides

Building blocks of DNA and RNA; composed of a phosphate group, a nitrogenous base, and a five-carbon sugar.

Phosphate group

A negatively charged group attached to nucleotides; part of the DNA/RNA backbone.

Pentose (five-carbon sugar)

Sugar component of nucleotides; ribose in RNA, deoxyribose in DNA.

Ribose

Five-carbon sugar in RNA, with a hydroxyl group at the 2' carbon.

Deoxyribose

Five-carbon sugar in DNA, lacking the 2' hydroxyl group.

Phospholipid

Lipid with two fatty acid tails and a phosphate-containing head; major membrane component.

Triglyceride

Lipid with three fatty acid tails attached to glycerol.

Saturated fat

Fatty acids with no double bonds; fully hydrogenated; typically solid at room temperature.

Unsaturated fat

Fatty acids with one or more double bonds; kinked; typically liquid at room temperature.

Amino acid

Building blocks of proteins; have an amino group, a carboxyl group, an α-carbon, a hydrogen, and an R-group.

R-group (side chain)

Variable side chain of an amino acid that determines its properties and identity.

20 amino acids

There are twenty standard amino acids that make up proteins.

Peptide bond

Covalent bond linking amino acids in a protein through dehydration synthesis.

Polypeptide

A chain of amino acids linked by peptide bonds that folds into a protein.

Sickle cell disease

A pleiotropic condition caused by a single amino acid substitution in hemoglobin.

Pleiotropy

A single gene influencing multiple phenotypic traits.

Polygenic trait

A trait influenced by multiple genes, such as height or skin color.

Colloid

A mixture in which dispersed particles (e.g., proteins in plasma) remain suspended in a medium.

Suspension

A mixture with larger particles (e.g., blood cells) that can settle out over time.

Simple diffusion

Passive movement of small, nonpolar molecules across the membrane down their gradient.

Facilitated diffusion

Passive transport via membrane proteins (channels/transporters) down the gradient.

Active transport

Movement against a gradient that requires energy (ATP), e.g., Na+/K+ pump.

Secondary active transport

Transport driven by another gradient (e.g., Na+ gradient) rather than directly by ATP.

Endocytosis

Process of taking in material via vesicles; includes pinocytosis, phagocytosis, and receptor-mediated endocytosis.

Phagocytosis

Endocytosis of large particles; “cell eating.”

Pinocytosis

Non-specific uptake of extracellular fluid by endocytosis.

Receptor-mediated endocytosis

Endocytosis that is highly specific, triggered by binding to cell-surface receptors.

Exocytosis

Release of substances from a cell via vesicle fusion with the plasma membrane.

Epithelial tissue

Tissue that lines surfaces and forms glands; avascular and tightly packed.

Connective tissue

Tissue that supports, binds, or protects; includes bone, cartilage, adipose, blood.

Areolar connective tissue

Loose connective tissue in the papillary dermis; richly vascularized.

Dense irregular connective tissue

Connective tissue with collagen fibers in multiple directions; found in dermis.

Dense regular connective tissue

Fibers aligned in parallel (e.g., tendons/ligaments) for strength in one direction.

Hyaline cartilage

Glassy cartilage; most common type; found at ends of long bones and in the trachea; avascular.

Elastic cartilage

Cartilage with high elasticity (ear).

Fibrocartilage

Cartilage with abundant collagen; resistance to compression (intervertebral discs, pubic symphysis).

Osteoblast

Bone-forming cell that secretes osteoid and becomes embedded as osteocytes.

Osteoclast

Bone-resorbing multinucleated cell that dissolves mineralized bone matrix.

Osteocyte

Mature bone cell embedded in lacunae; maintains bone tissue via canaliculi.

Lamellae

Concentric layers of bone matrix around a central canal.

Circumferential lamellae

Bone lamellae that run around the outer circumference of a bone.

Primary ossification center

First site of bone formation in endochondral ossification, usually in the diaphysis.

Secondary ossification centers

Sites of bone formation at the ends of long bones in endochondral ossification.

Epiphyseal plate (growth plate)

Cartilaginous zone enabling longitudinal bone growth in children.

Epiphyseal line

Remnant of the growth plate after growth stops.

Intramembranous ossification

Bone formation directly from mesenchyme; forms most skull bones and clavicles.

Endochondral ossification

Bone formation by replacing cartilage; forms most long bones.

Periosteum

Outer fibrous membrane covering bone; site of growth and repair.

Calcitonin

Thyroid hormone that lowers blood calcium by stimulating osteoblast activity.

Parathyroid hormone (PTH)

Hormone that raises blood calcium by stimulating osteoclasts, kidney calcium reabsorption, and intestinal calcium absorption via calcitriol.

Calcitriol (vitamin D3)

Active vitamin D; promotes intestinal calcium absorption and supports bone resorption with PTH.

Rickets

Pediatric bone disease from vitamin D/calcium deficiency; bowing of legs.

Osteoporosis

Decreased bone density with increased fracture risk due to imbalanced bone remodeling.

Turner syndrome

Monosomy X; typically only females; absence of functional Y leading to lack of male genital development.

Down syndrome (trisomy 21)

Condition caused by nondisjunction resulting in three copies of chromosome 21, not a gene mutation.

Serous membrane

Thin, watery membrane lining ventral body cavities; composed of simple squamous epithelium over a connective tissue layer.

Simple squamous epithelium

Flat, single-layer epithelium ideal for diffusion and serous membranes.

Simple columnar epithelium with microvilli

Narrow tall cells with microvilli in the small intestine to maximize nutrient absorption; underlain by areolar connective tissue.

Pseudostratified ciliated columnar epithelium

Epithelium with a falsely layered appearance; has cilia and goblet cells (e.g., trachea).

Goblet cells

Mucus-secreting cells interspersed in epithelium; important for mucus production.

Keratinocytes

Most abundant epidermal cells that produce keratin for waterproofing.

Melanocytes

Pigment-producing cells that synthesize melanin; vary with sun exposure; polygenic trait.

Dendritic (Langerhans) cells

Immune cells in the epidermis that present antigens; dendritic processes.

Merkel (tactile) cells

Receptors for gentle touch located in the epidermis.