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Overview of Major Human Body Systems

May 11, 2025

Respiratory System

Importance

  • Facilitates breathing
  • Oxygen intake & carbon dioxide expulsion

Components

  • Nose, mouth, pharynx, larynx, trachea, bronchi, lungs

Main Functions

  1. Pulmonary Ventilation: Air travels through the nose/mouth → pharynx → larynx → trachea → lungs
  2. External Respiration: Oxygen enters lungs, CO2 is expelled
  3. Internal Respiration: Gases exchange between bloodstream and tissues
  4. Sound Production: Air flow through larynx vibrates vocal cords
  5. Olfactory Function: Smell depends on olfactory fibers in the nose

Carbon Dioxide Regulation

  • Hypercapnia: Excess CO2 causing health issues like fatigue, headaches

Upper Respiratory Tract

  • Structures: Nose, nasal cavity, mouth, pharynx, larynx
  • Nose: Smell, air filter, sinus system
  • Pharynx Sections: Nasopharynx, oropharynx, hypopharynx
  • Larynx: Voice box, airway protection

Lower Respiratory Tract

  • Components: Trachea, lungs, bronchi, diaphragm
  • Lungs Protection: Sternum, ribcage, vertebrae
  • Lung Function: Oxygen intake, CO2 expulsion, surfactant production
  • Bronchi & Diaphragm: Air passage, breathing muscle

Respiratory Zones

  • Conducting Zone: Air passage (nose, pharynx, larynx, trachea, bronchi, bronchioles)
  • Respiratory Zone: Gas exchange (bronchioles, alveolar ducts, alveoli)

Ventilation Process

  • Inhalation/Exhalation: Diaphragm movement
  • Breathing Issues: Hyperventilation, hypoventilation consequences

Cardiovascular System

Introduction

  • Composed of the heart, blood vessels, and blood
  • Cardiopulmonary system: Cardiovascular + pulmonary components

Heart Anatomy

  • Muscle located in chest, size of a clenched fist
  • Chambers: Right & left atrium, right & left ventricle
  • Valves: Right AV (tricuspid), pulmonary, aortic, left AV (mitral)

Blood Circulation

  • Pulmonary Circulation: Heart ↔ Lungs
  • Systemic Circulation: Heart ↔ Body
  • Pathway: Vena cava → Right atrium → Right ventricle → Lungs → Left atrium → Left ventricle → Aorta

Blood Components

  • Plasma, red blood cells, white blood cells, platelets
  • Functions: Oxygen & nutrient transport, infection defense, waste removal, clotting

Gastrointestinal System

Overview

  • Digestive process: Ingestion, digestion, absorption, waste elimination

Anatomy

  • Solid Organs: Liver, gallbladder, pancreas
  • Hollow Organs: Mouth, esophagus, stomach, intestines, anus

Functions

  • Nutrient breakdown & absorption, waste movement via peristalsis

Stomach Parts

  • Cardia, fundus, body, antrum, pylorus

Intestinal Sections

  • Small Intestine: Duodenum, jejunum, ileum
  • Large Intestine: Ascending, transverse, descending, sigmoid colon

Enzyme Functions

  • Carbohydrates: Amylase, maltase
  • Proteins: Pepsin, trypsin
  • Nucleic Acids: Nuclease, nucleosidase
  • Lipids: Lipase, bile salts

Muscular System

Overview

  • Controls movement, posture, voluntary/involuntary movements

Types of Muscles

  1. Skeletal Muscles: Movement, posture, voluntary actions
  2. Cardiac Muscles: Heart function, involuntary
  3. Smooth Muscles: Organs like intestines & stomach, involuntary actions

Muscle Proteins

  • Myosin & Actin: Role in muscle contraction

Muscle Groups

  • Head/Neck, Chest/Back, Abdomen, Arms/Hands, Legs/Feet

Endocrine System

Functions

  • Regulates growth, reproduction, stress

Glands

  • Pituitary, Thyroid, Parathyroid, Adrenal, Ovaries, Testes

Hormones

  • GH, prolactin, cortisol, endorphins, etc.

Pituitary Gland Sections

  • Anterior: Produces growth, stress hormones
  • Posterior: Vasopressin, oxytocin

Urinary System

Functions

  • Waste elimination, chemical/water balance, blood regulation

Components

  • Kidneys, Ureters, Bladder, Urethra

Kidney Function

  • Nephrons: Filter blood, regulate fluid

Waste Movement

  • Ureters: Kidney to bladder transport
  • Bladder/Urethra: Urine storage & expulsion

Immune System

Functions

  • Fights pathogens, protects body through lymphatic system

Key Components

  • Lymph, Lymph Nodes, Lymphatic Vessels, White Blood Cells

Lymphatic System

  • Lymph Nodes: Filter harmful substances
  • White Blood Cells: Five types, fight infection

Skeletal System

Functions

  1. Body support
  2. Movement
  3. Organ protection
  4. Blood cell production
  5. Mineral storage
  6. Endocrine regulation

Divisions

  • Axial Skeleton: Skull, vertebrae, rib cage
  • Appendicular Skeleton: Limbs, girdles

Bone Types

  • Compact & Cancellous Bones: Structure, protection, blood production

Nervous System

Functions

  • Information collection, processing, acting on stimuli

Divisions

  • Central Nervous System (CNS): Brain & spinal cord
  • Peripheral Nervous System (PNS): Nerves, ganglia

Brain Regions

  • Cerebellum, Cerebrum, Medulla, Brain Stem, Thalamus, Hypothalamus

CNS & PNS

  • Somatic & Autonomic Systems: Voluntary & involuntary controls

Integumentary System

Overview

  • Skin layers, temperature regulation, gland functions

Skin Layers

  • Epidermis, Dermis, Subcutaneous Layer

Glands

  • Sebaceous & Sweat Glands: Exocrine functions

Reproductive Systems

Male System Components

  • External Genitalia: Penis, scrotum
  • Internal Organs: Testes, seminal vesicles, prostate gland

Female System Components

  • External Genitalia: Labia, clitoris
  • Internal Organs: Ovaries, uterus, fallopian tubes

Reproductive Functions

  • Sperm & egg production, fertilization, sexual characteristics

This summary provides an overview of the key functions and components of several major human body systems. Each system contributes to the overall health and function of the body, highlighting their interconnectivity and importance.