body system

Digestive System

Breaks down food to extract nutrients and energy for survival.

Main Organs of Digestion

Mouth, esophagus, stomach, intestines, liver, pancreas.

Stomach

Uses gastric acids to break down food.

Small Intestine

Absorbs nutrients into the bloodstream.

Excretory System

Removes waste and maintains water and electrolyte balance.

Kidneys

Filter blood and produce urine.

Ureters, Bladder, Urethra

Transport and store urine before excretion.

Respiratory System

Enables gas exchange, supplying oxygen and removing carbon dioxide.

Main Structures of Respiratory System

Lungs, trachea, diaphragm.

Alveoli

Tiny air sacs where gas exchange occurs.

Circulatory System

Transports oxygen, nutrients, and waste throughout the body.

Heart

Muscular organ that pumps blood through the body.

Blood Vessels

Include arteries (carry oxygenated blood), veins (carry deoxygenated blood), and capillaries (site of gas exchange).

Right Atrium

Receives deoxygenated blood from the body.

Right Ventricle

Pumps deoxygenated blood to the lungs via the pulmonary artery.

Left Atrium

Receives oxygenated blood from the lungs.

Left Ventricle

Pumps oxygenated blood to the body through the aorta.

Capillaries

Tiny blood vessels where oxygen and carbon dioxide exchange occurs.

Pulmonary Capillaries

Oxygen enters the blood, and carbon dioxide is expelled.

Systemic Capillaries

Oxygen is delivered to tissues, and carbon dioxide is collected for removal.

Nervous System

Controls body functions and responses to stimuli.

Central Nervous System (CNS)

Includes the brain and spinal cord; processes information.

Peripheral Nervous System (PNS)

Transmits signals between CNS and the body.

Neurons

Nerve cells that send electrical signals.

Normal Nervous Response

Involves brain processing; slower but coordinated.

Reflex Response

Automatic and rapid; processed by the spinal cord, not the brain.

Endocrine System

Regulates body functions through hormones.

Hormones

Chemical messengers traveling through the bloodstream.

Hypothalamus

Links the nervous system to the endocrine system.

Pituitary Gland

"Master gland" that regulates other glands.

Thyroid Gland

Controls metabolism and energy levels.

Lymphatic System

Helps with immunity and fluid balance.

Lymph

Fluid containing white blood cells and waste products.

Lymph Nodes

Filter lymph and trap harmful substances.

Spleen

Removes old blood cells and supports immune function.

Immune Surveillance

Identifies and fights infections.