Overview
This lecture provided an overview of the major human organs, their locations, structures, and primary functions within the body's systems.
The Brain
- The brain is the body's control center, protected by the skull.
- It consists of two hemispheres connected by the corpus callosum, each divided into lobes.
- Frontal lobe manages thinking, decision-making, motor skills, and speech.
- Parietal lobe organizes and interprets sensory information.
- Occipital lobe processes visual information and reading.
- Temporal lobe handles auditory processing, memory, and language comprehension.
- Cerebellum controls fine motor skills, balance, and posture.
- Brain stem (midbrain, pons, medulla oblongata) controls vital involuntary functions.
Lungs & Respiratory System
- Lungs provide oxygen to the blood and remove carbon dioxide.
- Air enters via trachea, splits into bronchi, then bronchioles, ending in alveoli where gas exchange occurs.
- Oxygen diffuses into blood; carbon dioxide is expelled during exhalation.
Heart & Circulatory System
- Heart pumps blood via a double circulatory system.
- Right side receives deoxygenated blood and sends it to the lungs; left side pumps oxygenated blood to the body.
- Four chambers: right/left atria, right/left ventricles.
- Valves prevent backflow: tricuspid, pulmonary, mitral, aortic.
- Veins carry blood to heart; arteries carry blood away.
Spleen
- Spleen filters blood, removes old cells, stores blood, and produces white blood cells to fight infection.
Digestive Organs
Stomach
- Stomach digests food using muscles and gastric juices; regulates flow to small intestine.
Pancreas
- Pancreas produces digestive enzymes and hormones for blood sugar regulation (insulin, glucagon).
Liver and Gallbladder
- Liver purifies blood, processes nutrients, detoxifies substances, produces bile, proteins, and cholesterol.
- Gallbladder stores and releases bile to help with fat digestion.
Kidneys & Urinary System
- Kidneys filter blood, maintain chemical balance, and remove waste as urine.
- Each kidney contains nephrons for filtration; urine travels to bladder via ureters.
- Kidneys also regulate water, secrete hormones, and activate vitamin D.
- Bladder stores urine until excretion.
Small & Large Intestines
- Small intestine digests food and absorbs nutrients.
- Large intestine absorbs water and salt, forming solid waste for excretion.
Key Terms & Definitions
- Alveoli — tiny air sacs in lungs for gas exchange.
- Atrium (atria) — upper heart chambers.
- Ventricle — lower heart chambers.
- Nephron — functional filtration unit of the kidney.
- Bile — digestive fluid from liver stored in gallbladder.
- Diastole/Systole — heart's relaxation/filling and contraction/pumping phases.
- Insulin/Glucagon — hormones from pancreas regulating blood sugar.
Action Items / Next Steps
- Review provided diagrams (if available) for heart and brain structures.
- Study the sequence of blood flow in the heart and gas exchange in lungs.
- Complete any assigned reading on organ systems (not specified in this lecture).