Respiratory System

• Function:

Supplies oxygen to the blood and removes carbon dioxide.

• Key Components:

Nose/Nasal Cavity: Filters, warms, and moistens air.

Pharynx: Passageway for air and food.

Larynx (Voice Box): Directs air to the trachea; houses vocal cords.

Trachea (Windpipe): Airway to lungs, reinforced with cartilage rings.

Bronchi/Bronchioles: Branches leading to lungs and alveoli.

Lungs: Organs for gas exchange; right lung (3 lobes), left lung (2 lobes).

Alveoli: Site of gas exchange with capillaries.

• Gas Exchange Process:

Inhalation: Diaphragm and intercostal muscles expand the thoracic cavity.

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

Exhalation: Diaphragm relaxes, expelling air from lungs.

• Disorders:

Asthma: Inflammation/narrowing of airways.

COPD: Progressive breathing difficulty (emphysema, bronchitis).

Pneumonia: Infection causing inflamed air sacs.

Lung Cancer: Uncontrolled cell growth in lungs.

Circulatory System

• Function:

Transports oxygen, nutrients, hormones, and wastes.

• Key Components:

Heart: Four chambers (atria, ventricles) pump blood; valves ensure one-way flow.

Blood Vessels:

Arteries: Carry oxygenated blood away from the heart.

Veins: Return deoxygenated blood to the heart.

Capillaries: Sites of exchange between blood and tissues.

Blood:

RBCs: Transport oxygen.

WBCs: Fight infections.

Platelets: Aid in clotting.

Plasma: Carries cells, nutrients, and waste.

Circulatory Pathways:

Pulmonary Circulation: Right ventricle → lungs → left atrium.

Systemic Circulation: Left ventricle → body → right atrium.

Disorders:

Hypertension: High blood pressure.

Coronary Heart Disease: Blocked coronary arteries.

Heart Failure: Heart’s inability to pump efficiently.

Stroke: Blockage or rupture in brain vessels.

Digestive System

• Function:

Breaks down food into absorbable nutrients.

• Key Components:

Mouth: Chewing and saliva start digestion.

Pharynx/Esophagus: Food passage to stomach.

Stomach: Churns food; gastric juices start protein digestion.

Small Intestine: Major digestion/absorption; aided by bile and pancreatic enzymes.

Accessory Organs: Liver (bile), gallbladder (bile storage), pancreas (digestive enzymes).

Large Intestine: Absorbs water, forms feces.

• Digestive Processes:

Ingestion: Taking in food.

Mechanical Digestion: Chewing, stomach churning.

Chemical Digestion: Enzymatic breakdown in the mouth, stomach, and small intestine.

Absorption: Nutrients absorbed in the small intestine.

Excretion: Removal of waste via defecation.

• Disorders:

GERD: Acid reflux.Peptic Ulcers: Stomach/duodenal sores.

IBD: Chronic inflammation (Crohn’s, ulcerative colitis).

IBS: Abdominal discomfort, bowel habit changes.

Gallstones: Bile imbalances leading to stones.

Excretory System

• Function:

Removes waste, maintains water/electrolyte balance.

• Key Components:

Kidneys:

Filter blood, form urine.

Ureters: Transport urine to the bladder.

Bladder: Stores urine.

Urethra: Expels urine.

Excretory Processes:

Filtration: Blood filtered in the kidneys.

Reabsorption: Useful substances reabsorbed into blood.

Excretion: Waste expelled as urine.