Skin

Hair

Nails

Sweat glands

Sebaceous (oil) glands

Functions of the Integumentary System:

Protection: The skin acts as a barrier against pathogens, chemicals, and physical injury, protecting internal tissues.

Regulation of body temperature: Sweat glands and blood vessels in the skin help regulate heat by sweating and dilating or constricting blood vessels.

Sensation: The skin contains sensory receptors that allow for the detection of touch, pressure, temperature, and pain.

Excretion: Sweat glands excrete waste products like salts, water, and urea through perspiration.

Vitamin D synthesis: The skin synthesizes vitamin D when exposed to sunlight, which is important for calcium absorption and bone health.

Water retention: The outermost layer of skin, the epidermis, helps prevent dehydration by reducing water loss from the body.

Immune defense: The skin provides an immune function by housing specialized cells that detect and fight infections.

Lymph nodes

Lymphatic vessels

Spleen

Thymus

Tonsils

Bone marrow

Functions of the Lymphatic System:

Fluid balance: It returns excess interstitial fluid (which surrounds cells) back to the bloodstream, preventing tissue swelling (edema).

Immune response: Lymph nodes and other lymphatic organs filter out pathogens, debris, and abnormal cells, initiating an immune response.

Absorption of dietary fats: Specialized lymphatic vessels called lacteals absorb fats and fat-soluble vitamins from the digestive system and transport them to the bloodstream.

Production of immune cells: The bone marrow and thymus produce and mature lymphocytes (white blood cells), essential for fighting infections.

Transport of lymph: Lymphatic vessels collect lymph (a fluid containing white blood cells, waste, and debris) and return it to the blood circulatory system.

Filtering of blood: The spleen filters blood, removing old or damaged red blood cells, and helps fight certain kinds of bacteria.

• the lungs are made of smooth muscle

• Gas exchange (oxygen in, carbon dioxide out)

• Breathing

• Lungs, Trachea, Bronchi

• Lungs: Exchange oxygen and carbon dioxide.

• Trachea: Connects mouth/nose to lungs.

• Major Process: Oxygen and carbon dioxide exchange.

  Inhalation: Air enters lungs via trachea, bronchi, and alveoli.

  Gas Exchange: Oxygen diffuses into blood from alveoli, CO2 diffuses out.

  Exhalation: Removes carbon dioxide.

  Respiratory Regulation: Diaphragm and intercostal muscles control breathing.

  Oxygen Utilization: Oxygen is transported to tissues and used in cellular respiration.

MECHANICAL DIGESTION: when the body physically increases
the surface area of food by breaking it down (such as when you
chew your food) or when the stomach churns and compresses
the food, improving chemical digestion (enzymatic) efficiency.

CHEMICAL DIGESTION: when the body breaks down food
using ENZYMES, special proteins that produce chemical
reactions.

Major Process: Breaks down food into absorbable nutrients and eliminates waste.

Mouth: Chewing and saliva start digestion (enzymes like amylase break down starch).

Stomach: Acids and enzymes digest proteins; churning creates chyme.

Small Intestine: Nutrients absorbed via villi and microvilli.

Liver: Produces bile to emulsify fats.

Pancreas: Produces digestive enzymes and regulates blood sugar through insulin.

Large Intestine: Absorbs water, forms solid waste.

Defecation: Elimination of waste through the anus.

Kidneys

Ureters

Bladder

Urethra

Functions of the Urinary System:

Filtration of blood: The kidneys filter blood to remove waste products and excess substances.

Waste excretion: It eliminates metabolic wastes, toxins, and drugs through urine.

Regulation of blood pressure: The kidneys control blood pressure by adjusting blood volume through water excretion.

Electrolyte balance: Maintains proper levels of key electrolytes like sodium, potassium, and calcium.

pH regulation: Balances the body's acid-base levels by excreting hydrogen ions and reabsorbing bicarbonate.

Water balance: Controls the amount of water retained or excreted by the body.

Hormone production: Produces hormones such as erythropoietin (stimulates red blood cell production) and renin (regulates blood pressure).