A&P first year

Myocytes

Cells responsible for generating the contractil force of a muscle

control inlet/ outlet functions

Sphincters encercle openings to restrict/ enable movment (swallow — sphincter opens — food enters, urinary retention — sphincter closed — urine remains in the bladder)

Isotonic contractions

Muscle leg-ngth changes with constant force

Isometric contractions

Muscle does not change with constant force

Titin

An elastic protein that stablilizes sarcomeres and helps restore it to length after contracting.

Hormones that increse protein synthesis

Growth hormone, testosterone

Hormone increases the rate of energy use

Thyroid hormone

Hormone potentiates muscle tissue

Epinephrine

Endomysium

Bundles the fiber
Contains capillary network
Location of the myosaetllite cells (stem cells)

Perimysium

Bundle fibers into a fascicle

Contains cappillary network

Epimysium

Bundles fascicles into a muscle

Most durable layer 

Blends into epimysium to for a tendon

Anatomical Position

Standing upright, facing forward, arms at sides, palms forward — the reference for all anatomical descriptions.

Supine Position

Lying on the back, face upward.

Prone Position

Lying on the stomach, face downward.

Etymology

Study of word origins; helps decode medical terms (e.g., "isch-" = restraint; "-emia" = blood condition).

Ischemia

Restricted blood flow to tissue ("isch-" = restraint + "heme" = blood + "-ia" = condition).

Hypoxemia

Low oxygen level in the blood ("hypo-" = below; "oxys" = oxygen; "-emia" = blood condition).

Hypoxia

Low oxygen level in tissues; causes fatigue, cyanosis, confusion.

Anoxia

Absence of oxygen supply.

Sagittal Plane

Divides the body into left and right halves (mid-sagittal = equal halves).

Coronal (Frontal) Plane

Divides body into anterior (front) and posterior (back) sections.

Transverse (Horizontal) Plane

Cuts body into superior (upper) and inferior (lower) parts.

Oblique Plane

Cuts the body at an angle other than 90 degrees.

Anterior (Ventral)

Toward the front of the body.

Posterior (Dorsal)

Toward the back of the body.

Superior (Cranial)

Toward the head or upper part.

Inferior (Caudal)

Toward the feet or lower part.

Medial

Toward the midline.

Lateral

Away from the midline.

Proximal

Closer to the point of limb attachment.

Distal

Farther from the point of limb attachment.

Superficial

Near the body surface.

Deep

Farther from the body surface.

Ipsilateral

On the same side of the body.

Contralateral

On the opposite side of the body.

Dorsolateral

Toward the back and side.

Protraction

Moving a body part forward (e.g., jaw forward).

Retraction

Moving a body part backward (e.g., jaw backward).

Flexion

Decreasing the angle of a joint.

Extension

Increasing the angle of a joint.

Abduction

Movement away from the midline.

Adduction

Movement toward the midline.

Rotation

Turning movement around a longitudinal axis.

Circumduction

Circular motion of a limb that traces a cone.

Elevation

Raising a body part (e.g., shrugging shoulders).

Depression

Lowering a body part (e.g., relaxing shoulders).

Dorsal Body Cavity

Cranial + Spinal cavities.

Ventral Body Cavity

Thoracic + Abdominopelvic cavities.

Thoracic Cavity

Contains mediastinum and left/right pleural cavities.

Abdominal Subregions

Nine-region method using mid-clavicular and trans-umbilical lines.

Axial Skeleton

Skull, ribs, vertebral column.

Appendicular Skeleton

Limbs and girdles (attachments).

Intra-individual Variation

Differences within one person (time of day, posture, diet).

Inter-individual Variation

Differences between people (age, sex, genetics, lifestyle).

Environmental Variation

Differences caused by surroundings (altitude, temperature, chemicals).

Anatomical Variation Examples

Extra rib, missing pyramidalis muscle, varied blood vessel paths.

X-inactivation

Random shutting off of one X chromosome in females → mosaic traits.

MHC Diversity

Genetic immune variation affecting mate preference ("sweaty T-shirt test").

Gut & Skin Microbiota

Microbes that affect digestion, immunity, mood ("human ecosystem").

Telomeres

Chromosome end caps that shorten with each cell division; linked to aging and cancer.

Nucleus

Label for the central part of a cell.

Plasma Membrane

Label for the outer boundary of a cell.

Cytoplasm

Label for the gel-like substance within a cell.

Mitochondrion

Organelle responsible for energy production.

Golgi Apparatus

Organelle involved in modifying, sorting, and packaging proteins.

Rough Endoplasmic Reticulum (Rough ER)

Organelle studded with ribosomes, involved in protein synthesis.

Smooth Endoplasmic Reticulum (Smooth ER)

Organelle involved in lipid synthesis and detoxification.

Ribosomes

Small structures that synthesize proteins.

Lysosome

Vesicle containing enzymes for digestion.

Peroxisome

Vesicle that breaks down fatty acids.

Centrioles

Structures involved in cell division.

Cytoskeleton

Network of fibers providing structural support (Actin, Intermediate, Microtubules).

Cilia or Flagella

Hair-like extensions that aid in cell movement.

Glycocalyx

Component on cell surface known as the 'Sugar Coat'.

Extracellular Matrix (ECM)

Structure providing support and anchorage to cells.

Transmembrane Protein

Molecule that spans the cell membrane.

Simple Diffusion

Process of molecules moving from high to low concentration.

Facilitated Diffusion

Process of molecules passing through a protein channel.

Osmosis

Movement of water across a membrane.

Primary Active Transport

Process using ATP to pump ions against their gradient.

Secondary Active Transport

Process where the gradient of one molecule drives the transport of another.

Phagocytosis

Process of a cell engulfing a particle (form of Endocytosis).

Exocytosis

Process of a cell releasing material via vesicle fusion.

Negative Feedback Loop

Loop that regulates hormone levels by counteracting changes.

Positive Feedback Loop

Loop that amplifies a response in the system.

Tissue

A group of similar cells performing a coordinated physiological function, held together by cell junctions and extracellular matrix.

Extracellular Matrix (ECM)

Non-cellular network of macromolecules surrounding cells; provides structural and biochemical support.

Epigenetic Regulation

Turning genes "on" or "off" without altering DNA sequence; determines tissue identity.

Teratoma

Tumor showing multiple tissue types due to loss of epigenetic silencing.

Four Major Tissue Types

Epithelial, Connective, Muscle, Nervous.

Epithelial Tissue

Layers of cells covering body surfaces or lining internal cavities; includes glands derived from epithelia.

Functions of Epithelial Tissue

Protection, permeability control, sensation, and secretion.

Epithelial Features

Polarity (apical/basal sides), cellularity (tightly bound cells), avascularity, and regeneration.

Basement Membrane

Thin non-cellular ECM layer anchoring epithelium; supports growth/repair; made of basal lamina + reticular lamina.

Cell Junctions

Specialized connections between cells (tight junctions, desmosomes, gap junctions) providing adhesion and communication.

Simple Epithelium

Single-cell-layer tissue allowing absorption and secretion.

Stratified Epithelium

Multiple layers for protection from friction or stress.

Squamous Epithelium

Flat, thin cells for diffusion (e.g., lungs, capillaries).

Cuboidal Epithelium

Cube-shaped cells for secretion and absorption (e.g., kidney tubules).

Columnar Epithelium

Tall cells for absorption and secretion (e.g., intestines).