Comprehensive Anatomy and Physiology of Human Body Systems

Anatomy

It studies the structures of the body.

Physiology

It studies the functions of the body.

Atom

The smallest unit of matter (e.g., carbon, oxygen).

Molecule

Atoms bonded together (e.g., water, glucose, proteins).

Organelle

structures inside cells

Cell

The basic unit of life (e.g., muscle cell, nerve cell).

Tissue

Groups of similar cells working together (e.g., muscle tissue, nervous tissue).

Organ

Structures made of different tissues with specific functions (e.g., heart, skin).

Organ System

Groups of organs working together (e.g., circulatory system, digestive system).

Organism

The complete living being (e.g., a human).

Integumentary System

Function: Protects body from injury, infection, and dehydration; regulates temperature; houses sensory receptors. Organs: Skin, hair, nails, sweat glands, oil glands.

Skeletal System

Function: Provides structure and support, protects organs, produces blood cells, stores minerals. Organs: Bones, cartilage, ligaments, joints.

Muscular System

Function: Allows movement, maintains posture, produces heat. Organs: Skeletal muscles, smooth muscles, cardiac muscle, tendons.

Nervous System

Function: Controls and coordinates body activities, responds to stimuli, allows communication. Organs: Brain, spinal cord, nerves, sensory organs.

Endocrine System

Function: Regulates body processes with hormones (growth, metabolism, reproduction). Organs: Pituitary gland, thyroid, adrenal glands, pancreas, ovaries, testes.

Cardiovascular (Circulatory) System

Function: Transports oxygen, nutrients, hormones, and wastes; helps regulate temperature. Organs: Heart, blood, blood vessels (arteries, veins, capillaries).

Lymphatic/Immune System

Function: Returns fluid to blood, defends against infection and disease. Organs: Lymph nodes, lymph vessels, spleen, thymus, tonsils.

Respiratory System

Function: Exchanges oxygen and carbon dioxide between blood and air. Organs: Lungs, trachea, bronchi, diaphragm, larynx, pharynx.

Digestive System

Function: Breaks down food, absorbs nutrients, eliminates solid waste. Organs: Mouth, esophagus, stomach, small intestine, large intestine, liver, pancreas, gallbladder.

Urinary (Excretory) System

Function: Eliminates nitrogenous wastes, regulates water and electrolyte balance, maintains acid-base balance. Organs: Kidneys, ureters, bladder, urethra.

Reproductive System

Function: Produces gametes (sperm/eggs), enables fertilization, supports development of offspring. Organs: Male: Testes, penis, vas deferens, prostate. Female: Ovaries, uterus, fallopian tubes, vagina, mammary glands.

Axial region

Head, neck, trunk.

Appendicular region

Upper and lower limbs.

Superior (cranial)

Toward the head.

Inferior (caudal)

Toward the feet.

Anterior (ventral)

Toward the front.

Posterior (dorsal)

toward the back.

Medial

toward the midline.

Lateral

away from the midline.

Proximal

closer to point of attachment (limbs).

Distal

farther from point of attachment.

Superficial

toward the surface.

Deep

away from the surface.

Longitudinal section

cut along the long axis.

Cross-section (transverse)

cut across the structure.

Oblique section

cut at an angle.

Sagittal plane

divides body into right and left.

Midsagittal

divides body into equal halves.

Parasagittal

divides body into unequal halves.

Frontal (coronal) plane

divides body into anterior and posterior.

Transverse (horizontal) plane

divides body into superior and inferior.

Homeostasis

the body's ability to maintain internal stability for proper function.

Variable

this is the thing being measured in the body. It's the thing that changes and kept in balance.

Set point

normal range of a variable.

Receptor

the sensor, the thing that detects the variable. It detects a change in the environment.

Control center

receives a message from the receptor, it sounds out commands to fix the problem.

Effectors

it receives the command and fixes the problem.

Response

the action taken to correct the imbalance. It's what the effectors do.

Stimulus

the change in the internal or external environment that disrupts homeostasis.

Receptor (Sensor)

detects the stimulus and sends information to the control center.

Effector

the structure that carries out the response to correct the imbalance.

Negative Feedback Loop

A control mechanism that opposes or reverses a change in a variable to maintain homeostasis.

Purpose of Negative Feedback Loop

Keeps conditions near the set point.

Positive Feedback Loop

A control mechanism that amplifies a change instead of reversing it.

Purpose of Positive Feedback Loop

Drives processes to completion, rather than maintaining a set point.

Epithelial Tissue

One of the four major tissue types, characterized by closely packed cells that cover surfaces and line cavities.

Connective Tissue

One of the four major tissue types, characterized by a diverse range of cells and extracellular matrix that provides support and structure.

Muscle Tissue

One of the four major tissue types, responsible for movement through contraction.

Nervous Tissue

One of the four major tissue types, composed of neurons and neuroglia, responsible for transmitting signals.

Endocrine Glands

Glands that secrete hormones directly into the bloodstream.

Exocrine Glands

Glands that secrete substances through ducts to an epithelial surface.

Merocrine Glands

Glands that secrete their products by exocytosis without losing cellular material.

Apocrine Glands

Glands that lose part of their cell body during secretion.

Holocrine Glands

Glands that release entire cells filled with secretory products.

Goblet Cells

Unicellular glands that secrete mucus, found in various epithelial tissues.

Neurons

Specialized cells of nervous tissue that transmit nerve impulses.

Neuroglia

Supportive cells in nervous tissue that protect and assist neurons.

Serous Membranes

Membranes that line body cavities and secrete a lubricating fluid.

Mucous Membranes

Membranes that line body cavities and secrete mucus.

Synovial membranes

Membranes located in joint cavities that produce synovial fluid for lubrication.

Stages of tissue repair

Injury, Inflammation, Regeneration and/or Fibrosis are the major processes involved in tissue repair.

Inflammation

A response to injury involving chemicals that cause heat, redness, and swelling.

Regeneration

The process by which different tissue types restore themselves after injury.

Fibrosis

The healing process primarily involving scar tissue formation.

Tumor

An abnormal mass of tissue that can be benign or malignant.

Benign

A non-cancerous tumor that does not invade nearby tissues.

Malignant

A cancerous tumor that can invade nearby tissues and spread to other parts of the body.

Metastasis

The spread of cancer cells from the original tumor to other parts of the body.

Cancer risk factors

Genetics and environment can influence the likelihood of developing cancer.

Chemotherapy

A cancer treatment that uses drugs to kill cancer cells.

Radiation

A cancer treatment that uses high-energy particles to destroy cancer cells.

Surgery

A cancer treatment that involves the physical removal of tumors.

Integumentary system functions

Protection, temperature regulation, sensation, excretion, and Vitamin D synthesis.

Hypodermis

The layer below the dermis composed mainly of adipose and areolar connective tissue.

Epidermis

The outermost layer of skin made of stratified squamous epithelial tissue.

Dermis

The middle layer of skin made primarily of dense irregular connective tissue.

Adipose tissue

A type of fat tissue that stores energy and provides cushioning.

Areolar connective tissue

A type of connective tissue that anchors skin to underlying structures.

Melanocytes

Cells in the epidermis that produce melanin for UV protection.

Collagen fibers

Strong connective tissue fibers found in the dermis that provide structure.

Elastic fibers

Fibers in the dermis that provide elasticity and flexibility to the skin.

Epidermal Strata

Layers of the skin with varying characteristics; includes alive and dead strata.

Melanin

A pigment that affects skin color and provides UV protection.

Keratin

A protein that provides structure and protection to the skin.

UV Light Effect on Melanin

UV light increases melanin production as a protective response.

Factors Affecting Skin Color

Genetics, exposure to sunlight, and certain medical conditions.

Dermal Structures

Includes blood vessels, nerves, and glands that support skin function.

Lines of Cleavage

Patterns of collagen fibers in the dermis that affect healing and scarring.

Accessory Organs of Skin

Includes glands, hair, and nails, each with specific functions.

Sebaceous Glands

Glands that secrete oil to lubricate skin and hair.