Human Body Systems Review

Respiratory System

• Takes in oxygen, removes carbon dioxide.
• Air passes through the trachea, bronchi, and lungs.
• Alveoli facilitate gas exchange.
• Diaphragm aids lung expansion/contraction.
• Epiglottis prevents food from entering the trachea.

Nervous System

• Controls body activities (voluntary and involuntary).
• CNS (brain and spinal cord) & PNS (other nerves).
• Neurons transmit electrical signals.
• Brain: cerebrum (thinking), cerebellum (movement), brainstem (automatic functions).
• Spinal cord: message relay between brain and body.

Digestive System

• Breaks down food for energy and nutrients.
• Mouth: chewing and saliva (enzymes).
• Esophagus leads to stomach (churning with acids).
• Small intestine: nutrient absorption; liver, pancreas, gallbladder aid digestion.
• Large intestine: water removal, feces formation.

Excretory System

• Removes waste.
• Kidneys filter blood, produce urine.
• Urine: ureters → bladder → urethra.
• Skin (sweat), lungs (carbon dioxide) remove waste.

Endocrine System

• Glands produce hormones for body control.
• Hormones: chemical messengers in blood.
• Pituitary gland: master gland.
• Adrenal glands: adrenaline (stress response).

Reproductive System

• Enables offspring creation.
• Male: sperm production in testes, delivery via urethra.
• Female: eggs in ovaries, fertilized egg growth in uterus.
• Fertilization: usually in fallopian tube, forms zygote.
• Menstrual cycle: prepares for pregnancy.

Sexually Transmitted Infections (STIs)

• Spread through sexual contact.
• Examples: HIV, chlamydia, gonorrhea, herpes.
• Bacterial (curable) or viral (treatable) causes.
• Prevention: safe sex, checkups.

Common Diseases and Conditions

• Bronchitis: inflamed bronchi.
• Pneumonia: lung infection.
• Ulcers: sores in stomach/intestines.
• Colon cancer: uncontrolled cell growth in colon.
• Lung cancer: often from smoking.