Comprehensive Anatomy and Physiology Study Guide: Terminology, Homeostasis, Histology, and Cytology

Nucleus

Control center of the cell; contains genomic DNA.

Nucleolus

Structure inside the nucleus that synthesizes ribosomes.

Cell / Plasma Membrane

Semi-permeable outer boundary that regulates what enters and exits the cell.

Cytoplasm

Gel-like fluid internal matrix in which organelles are suspended.

Mitochondria

Cellular powerhouse; synthesizes ATP energy via cellular respiration.

Ribosomes

Cellular structures that manufacture proteins.

Rough Endoplasmic Reticulum (Rough ER)

Network studded with ribosomes; assists in protein synthesis and processing.

Smooth Endoplasmic Reticulum (Smooth ER)

Synthesizes lipids and metabolizes/detoxifies drugs and toxins.

Golgi Apparatus / Body

Modifies, sorts, and packages proteins and lipids for transport (cellular post office).

Lysosomes

Organelles filled with enzymes to break down waste, debris, and cellular refuse (recycling center).

Vesicles

Small membrane-bound sacs involved in intracellular transport and storage.

Vacuole

Storage structure for water and essential cellular nutrients.

Centrioles

Specialized structures that organize microfilaments during cell division in animal cells.

Cytoskeleton / Microfilaments

Protein network that maintains structural shape and cellular organization.

Superior / Cranial

Above or toward the head.

Inferior / Caudal

Below or toward the feet.

Anterior / Ventral

Toward the front of the body.

Posterior / Dorsal

Toward the back of the body.

Medial

Toward the middle or center of the body.

Lateral

Away from the middle of the body.

Proximal

Closer to where a limb attaches to the body.

Distal

Farther away from where a limb attaches.

Superficial

Closer to the surface of the body.

Deep

Farther inside the body.

Prone

Lying face down.

Supine

Lying face up.

Homeostasis

The process of maintaining a stable internal environment within the body.

Negative Feedback Loop

A mechanism that reverses the direction of an initial change to return to normal baseline levels.

Positive Feedback Loop

A mechanism that increases or amplifies the original change.

Epithelial Tissue

Covers body surfaces and lines internal cavities and organs.

Connective Tissue

Supports, connects, and protects other tissues and organs.

Muscle Tissue

Contracts to produce physical movement.

Nervous Tissue

Receives, processes, and transmits electrical and chemical signals for communication.

Superior / Cranial

Above or toward the head (e.g., the head is superior to the chest).

Inferior / Caudal

Below or toward the feet (e.g., the stomach is inferior to the heart).

Anterior / Ventral

Toward the front of the body (e.g., the chest is anterior to the spine).

Posterior / Dorsal

Toward the back of the body (e.g., the spine is posterior to the chest).

Medial

Toward the middle or center of the body (e.g., the nose is medial to the eyes).

Lateral

Away from the middle of the body (e.g., the ears are lateral to the eyes).

Proximal

Closer to where a limb attaches to the body (e.g., the elbow is proximal to the wrist).

Distal

Farther away from where a limb attaches to the body (e.g., the fingers are distal to the elbow).

Superficial

Closer to the surface of the body (e.g., skin is superficial to muscles).

Deep

Farther inside the body (e.g., bones are deep to the skin).

Prone

Body position lying face down.

Supine

Body position lying face up (looking at the ceiling).

Lateral Recumbent

Body position lying on your side.

Standard Anatomical Position

Reference position where a person is standing upright, facing forward, head facing forward, arms at sides, palms facing forward, and feet facing forward.

Patient Orientation Rule

Right and left in anatomical descriptions refer strictly to the patient's right and left, not the viewer's.

RUQ (Right Upper Quadrant)

Abdominal quadrant containing the liver and gallbladder.

LUQ (Left Upper Quadrant)

Abdominal quadrant containing the stomach and spleen.

RLQ (Right Lower Quadrant)

Abdominal quadrant containing the appendix.

LLQ (Left Lower Quadrant)

Abdominal quadrant containing part of the large intestine.

Right Hypochondriac Region

Upper right abdominal region.

Epigastric Region

Upper middle abdominal region.

Left Hypochondriac Region

Upper left abdominal region.

Right Lumbar Region

Middle right abdominal region.

Umbilical Region

Center abdominal region surrounding the belly button.

Left Lumbar Region

Middle left abdominal region.

Right Iliac Region

Lower right abdominal region (sometimes variant-spelled as Right Illiac).

Hypogastric Region

Lower middle abdominal region.

Left Iliac Region

Lower left abdominal region.

Cranial Cavity

Dorsal cavity that encloses and contains the brain.

Vertebral / Spinal Cavity

Dorsal cavity that encloses and contains the spinal cord.

Thoracic Cavity

Ventral cavity containing the heart and lungs.

Abdominopelvic Cavity

Ventral cavity containing the stomach, liver, intestines, kidneys, bladder, and pelvic organs.

Diaphragm

Large dome-shaped muscle separating the thoracic cavity from the abdominal cavity; serves as the primary muscle for breathing.

Sagittal Plane

Divides the body vertically into right and left portions.

Midsagittal Plane

Divides the body directly down the midline into equal left and right halves.

Parasagittal Plane

Divides the body vertically into unequal left and right portions.

Frontal / Coronal Plane

Divides the body vertically into front (anterior) and back (posterior) portions.

Transverse Plane

Divides the body horizontally into top (superior) and bottom (inferior) portions.

Oblique Plane

Cuts through the body at an angle.

Homeostasis

The process of maintaining a stable internal environment within the body despite external changes.

Negative Feedback Loop

Homeostatic mechanism that reverses the direction of an initial change to return a physiological parameter toward normal baseline levels (the most common type).

Positive Feedback Loop

Homeostatic mechanism that increases or amplifies the original change, pushing the parameter further away from its initial state (e.g., childbirth, blood clotting).

Homeostatic Loop Sequence

Stimulus -> Receptor -> Control Center -> Effector -> Response.

Stimulus

A change in the internal or external environment that disturbs homeostasis.

Receptor / Sensor

Structure that detects an environmental change and sends input signals to the control center.

Control Center

Structure (typically the brain/hypothalamus) that evaluates input signals and determines the appropriate response.

Effector

Structure (such as sweat glands or muscles) that receives output signals and carries out the response.

Response

The resulting action of the effector that alters the internal environment to restore balance.

Axillary

Armpit region.

Acromial

Shoulder point region.

Sternal

Center of the chest.

Pectoral

Chest region.

Femoral

Thigh region.

Inguinal

Groin region.

Coxal

Hip region.

Brachial

Upper arm region.

Antebrachial

Forearm region.

Digital

Fingers or toes.

Pedal

Entire foot.

Plantar

Bottom / sole of the foot.

Crural

Lower leg region.

Patellar

Front of the knee.

Popliteal

Back of the knee.

Cervical

Neck region.

Orbital

Eye region.

Buccal

Cheek region.

Oral

Mouth region.