Chapter 05 | Organ Systems

Organ

A structure made of two or more types of tissues that work together to perform more complex functions than individual tissues.

Examples of organs

Heart, lungs, and kidneys.

Organ System

A group of organs that work together to perform more complex functions than an individual organ.

Examples of organ systems

Cardiovascular system includes the heart and blood vessels.

Integumentary System

The system comprising the skin and its appendages.

Primary function of skin

Acts as a barrier against mechanical damage, pathogens, chemicals, and UV radiation.

Hair (function)

Provides protection from UV radiation, helps regulate body temperature, and enhances sensory perception.

Nails (function)

Protect the tips of fingers and toes from mechanical damage and aid in picking up small objects.

Microscopic sense receptors function

Detect sensory changes such as pressure, touch, temperature, and pain.

Sweat glands function

Assist in regulating body temperature by releasing sweat through pores.

Oil glands (Sebaceous glands) function

Produce sebum, which lubricates the skin and hair, and helps prevent bacterial growth.

Skeletal System

The organ system that comprises bones, cartilage, and ligaments.

206

The number of named bones in the adult human body.

Cartilage (function)

Cushions and protects joints, reducing friction and absorbing shock during movement.

Ligaments

Tough bands of connective tissue that hold bones together at joints.

Types of joints

Ball-and-socket (shoulder), hinge (elbow), and pivot (neck) joints.

Support (skeletal system function)

Provides structure and shape to the body.

Protection (skeletal system function)

Protects vital internal organs such as the brain, heart, and lungs.

Movement (skeletal system function)

Facilitates movement by providing attachment points for muscles.

Mineral Storage (skeletal system function)

Stores essential minerals such as calcium and phosphorus.

Blood Cell Formation (Hematopoiesis)

Occurs in red bone marrow, producing red blood cells, white blood cells, and platelets.

Skeletal Muscles

Voluntary muscles responsible for movement of the body.

Smooth Muscles

Involuntary muscles found in the walls of hollow organs.

Cardiac Muscle

Specialized muscle found only in the wall of the heart.

Movement (muscular system function)

Skeletal muscles pull on bones to produce voluntary movements.

Posture Maintenance (muscular system function)

Helps maintain posture through continuous, low-level contractions.

Heat Production (muscular system function)

Generates heat as a byproduct of muscular activity.

Central Nervous System (CNS)

Comprised of the brain and spinal cord.

Peripheral Nervous System (PNS)

Includes cranial and spinal nerves that transmit signals between the CNS and the body.

Sense Organs

Eyes, ears, nose, tongue, and skin connect to the nervous system to receive stimuli.

Communication (nervous system function)

Transmits electrical and chemical signals for body coordination.

Integration (nervous system function)

Processes sensory input and generates appropriate responses.

Control (nervous system function)

Regulates voluntary and involuntary actions.

Endocrine System

Comprises glands that secrete hormones into the bloodstream.

Pituitary Gland

Known as the 'master gland,' it controls other endocrine glands.

Pineal Gland

Produces melatonin, regulating sleep-wake cycles.

Thyroid Gland

Produces hormones regulating metabolism.

Pancreas function

Produces insulin and glucagon to regulate blood sugar levels.

Heart (cardiovascular system)

A muscular organ that pumps blood throughout the body.

Blood Vessels

Arteries, veins, and capillaries that transport blood throughout the body.

Transportation (cardiovascular system function)

Delivers oxygen, nutrients, hormones, and eliminates waste products.

Body Temperature Regulation (cardiovascular system function)

Regulates body heat through blood vessel dilation and constriction.

Immunity (cardiovascular system function)

Blood contains white blood cells and antibodies for fighting infections.

Lymphatic System

Comprises vessels and nodes that transport lymph, a fluid containing white blood cells.

Immunity (lymphatic system function)

Provides defense against infections by transporting white blood cells.

Phagocytes

White blood cells that engulf and destroy pathogens.

Phagocytosis

Process where phagocytes engulf foreign particles.

Gas Exchange (respiratory system function)

Oxygen diffuses into the blood in alveoli; carbon dioxide diffuses out.

Alveoli

Tiny air sacs in the lungs for gas exchange.

Digestive System

Includes primary organs responsible for food processing and absorption.

Functions of Digestive System

Digestion, absorption, and elimination of waste.

Urinary System

Comprises kidneys, ureters, bladder, and urethra.

Excretion (urinary system function)

Removes waste products from the bloodstream.

Homeostasis

Maintenance of stable internal conditions by organ systems.

Organ Replacement

Methods to replace vital and nonvital organs for health.

Organ Transplantation

Surgical procedure to replace a failing organ.

Examples of prostheses

Artificial limbs, heart valves, and joint replacements.

Fluid Balance (lymphatic system function)

Returns excess tissue fluid to the bloodstream.

Immune System

Provides defense against pathogens through various immune responses.

Antibodies

Proteins that recognize and neutralize foreign substances.

Respiratory tract

Pathway for air, divided into upper and lower airways.

Acid-Base Balance (respiratory function)

Regulates pH of body fluids through carbon dioxide levels.

Alimentary Canal

The GI tract responsible for the passage and processing of food.

Accessory Organs

Organs aiding digestion, such as the liver and pancreas.

Mechanical Digestion

Breaking down food into smaller pieces, primarily in the mouth and stomach.

Chemical Digestion

Involves enzymes that break food down into absorbable components.

Absorption (digestive system)

Nutrients absorbed mainly in the small intestine.

Elimination (digestive system)

Removal of indigestible wastes as feces.

Kidneys (function)

Filter blood to remove waste products and form urine.

Urethra

Tube through which urine is expelled from the body.

Hormone Production (reproductive function)

Regulates reproductive processes and secondary sexual characteristics.

Testes function

Produce sperm and testosterone.

Ovaries function

Produce eggs and hormones such as estrogen and progesterone.

Uterus function

Houses and nourishes the developing fetus during pregnancy.

Fertilization

Process by which sperm meets and penetrates the egg.

Lymph Nodes

Structures that filter lymph and trap pathogens.

Thymus (immune system)

Produces T-cells essential for adaptive immunity.

Spleen (function)

Filters blood and helps fight infection.

Communication (endocrine function)

Hormones regulate various physiological processes.

Neuroendocrine System

Works with the nervous system to regulate long-term body functions.

Blood Pressure Regulation (urinary system function)

The kidneys help adjust blood volume and regulate pressure.

Prostheses (definition)

Artificial devices used to replace nonvital organs or body parts.

Joint Replacements

Artificial joints restoring mobility and relieving pain.

Cardiac Muscle function

Pumps blood throughout the body without fatigue.

Sebaceous glands

Oil glands producing sebum to lubricate skin.

Sweat glands (function in thermoregulation)

Release sweat to cool the body through evaporation.

Role of ligaments

Provide stability to joints connecting bones.

Role of cartilage

Absorbs shock and reduces friction in joints.

Functions of the skeletal system

Support, protection, movement, mineral storage, blood cell formation.

Biceps and triceps

Examples of skeletal muscles responsible for body movement.

Smooth muscles (examples)

Found in stomach and blood vessels aiding in digestion.

Major components of the CNS

Brain and spinal cord.

Spinal cord function

Major pathway transmitting signals within the body.

Function of capillaries

Sites of gas exchange between blood and tissues.

Layers of skin

Epidermis, dermis, and hypodermis.

Role of salivary glands

Produce saliva starting the digestion of carbohydrates.

Function of the appendix

May play a role in immunity.

Bile (definition)

Substance produced by the liver for fat digestion.

Alveolar function

Site for the exchange of oxygen and carbon dioxide.

Interdependence of Systems

All body systems are interconnected and affect each other.