Organ Systems

Chapter 5

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Learning Objectives: Lesson 5.1

Define and contrast the terms organ and organ system.
Identify and locate the major organs of the integumentary, skeletal, and muscular systems, and describe their major functions.
Identify and locate the major organs of the nervous, endocrine, and cardiovascular systems, and describe their major functions.

Definitions and Concepts

Organ: A structure made up of two or more kinds of tissues that can collectively perform more complex functions than a single tissue.
Organ System: A group of organs that perform functions more complex than can be performed by any single organ alone.

Integumentary System

Structure

Only one organ: The skin.
Appendages: Includes several structures attached to the skin:
- Hair
- Nails
- Microscopic sense receptors
- Sweat glands
- Oil glands

Functions

Primary Function: Protection
Regulation: Body temperature regulation through various mechanisms.
Chemical Synthesis: Produces essential chemicals (vitamin D).
Sense Organ: Provides sensory perception through receptors located in the skin.

Skeletal System

Structure

Bones: Composed of 206 named bones in the adult skeleton.
Variable Bones: Additional bones may occur in each individual.
Cartilage: Connects and cushions joints between bones.
Ligaments: Bands of fibrous tissue that hold bones together at joints.
Joints: Areas where bones connect, allowing for movement.

Functions

Support: Provides a framework for the entire body.
Protection: Shields the brain and internal organs.
Movement: Facilitates movement in conjunction with muscles.
Storage: Stores essential minerals such as calcium and phosphorus.
Blood Formation: Produces blood cells within the bone marrow.

Key Bones of the Body

Skull Bones: Parietal, Frontal, Occipital
Vertebrae
Facial Bones: Maxilla, Mandible
Clavicle
Scapula
Sternum
Rib Cage
Humerus, Radius, Ulna
Pelvis: Hip bones (coxal)
Femur, Patella, Tibia, Fibula
Tarsal, Metatarsal, and Phalanges

Muscular System

Structure

Muscles: Primary organs of the muscular system.
- Types of Muscle:
- Voluntary/Skeletal Muscle: Striated muscles that are under conscious control.
- Involuntary/Smooth Muscle: Found in the walls of some organs, not under conscious control.
- Cardiac Muscle: Specialized muscle found in the heart, involuntary in nature.

Functions

Movement: The primary function of muscle tissues which enables movement of the body and its parts.
Skeletomuscular System: This term refers to the combination of the skeletal and muscular systems working together.

Nervous System

Structure

Central Nervous System (CNS):
- Brain
- Spinal Cord
Peripheral Nervous System (PNS):
- Cranial nerves and their branches
- Spinal nerves and their branches
- Sense organs

Functions

Communication: Responsible for communication between body organs.
Integration: Integrates various body functions by processing information.
Control: Controls body functions through signaling.
Sensory Recognition: Recognizes sensory stimuli, transmitting information to the brain.

Endocrine System

Structure

Includes various glands such as:
- Pituitary Gland
- Pineal Gland
- Hypothalamus
- Thyroid Gland
- Parathyroid Glands
- Thymus Gland
- Adrenal Glands
- Pancreas
- Ovaries (in females)
- Testes (in males)

Functions

Communication: Similar to the nervous system, it facilitates communication and control.
Integration: Helps integrate bodily functions through hormone release.
Control: Controls functions at a slower pace but with longer-lasting effects (compared to the nervous system).
Neuroendocrine System: Interaction between the nervous and endocrine systems highlights their mutual functionality.

Cardiovascular System

Structure

Sometimes referred to as the circulatory system
Major components include:
- Heart
- Blood Vessels

Functions

Transportation: Transports oxygen, nutrients, hormones, and waste products throughout the body.
Temperature Regulation: Helps regulate the body’s temperature through blood flow.
Immunity: Plays a role in body defense mechanisms.

Lymphatic/Immune System

Structure

Lymphatic Vessels: Transport lymph fluid.
Lymph Nodes and Tonsils: Filter lymph and harbor immune cells.
Thymus: Site for T-cell maturation.
Spleen: Filters blood and supports immune responses.

Functions

Transportation: Carries lymph, which contains immune cells.
Immunity: Facilitates the body’s defense against pathogens.

Respiratory System

Structure

Includes:
- Nose
- Pharynx
- Larynx
- Trachea
- Bronchi
- Lungs

Functions

Gas Exchange: Exchanges carbon dioxide for oxygen in the alveoli.
Filtration: Filters irritants from the inspired air.
Acid-Base Balance: Helps regulate blood pH.

Digestive System

Structure

Primary Organs (GI Tract)

Mouth
Pharynx
Esophagus
Stomach
Small Intestine
Large Intestine
Rectum
Anal Canal

Accessory Organs

Assist in digestion:
- Teeth
- Salivary Glands
- Tongue
- Liver
- Gallbladder
- Pancreas
- Appendix

Functions

Digestion: Mechanical and chemical breakdown of food.
Absorption: Uptake of nutrients into the body.
Elimination: Removal of undigested waste (feces).

Urinary System

Structure

Components:
- Kidneys
- Ureters
- Urinary Bladder
- Urethra (part of both urinary and reproductive systems in males)

Functions

Blood Filtering: Clears waste products from the blood, which are excreted as urine.
Balance: Maintains electrolyte, water, and acid-base balance in the body.

Reproductive System

Male Reproductive System: Structure

Gonads:
- Testes
Other Structures:
- Vas deferens
- Urethra
- Prostate
- External genitalia (penis and scrotum)

Female Reproductive System: Structure

Gonads:
- Ovaries
Other Structures:
- Uterus
- Uterine (fallopian) tubes
- Vagina
- External genitalia (vulva)
- Mammary glands (breasts)

Functions of the Reproductive Systems

Gene Survival: Ensures the continuation of species through reproduction.
Sex Cell Production:
- Male: Produces sperm
- Female: Produces ova (eggs)
Fertilization: Involves transfer and fertilization of sex cells.
Offspring Development: Involves nurturing and developing offspring.
Hormone Production: Production of sex hormones critical for reproductive functions.

Body as a Whole

Overview

11 Body Systems:
- Integumentary
- Skeletal
- Muscular
- Nervous
- Endocrine
- Cardiovascular
- Lymphatic/Immune
- Respiratory
- Digestive
- Urinary
- Reproductive
Interdependence: No body system functions entirely independently; they are all structurally and functionally interconnected.
Homeostasis: The balance within the body can only be maintained through the coordinated functioning of all body systems.

Organ Replacement

Overview

Organ Functionality:
- Nonvital organ losses (e.g., limbs) may not be immediately life-threatening.
- Vital organ losses (e.g., heart, brain) are critical and life-threatening.
Replacement Strategies:
- Nonvital Organ Replacement: Use of prostheses.
- Vital Organ Transplantation: Surgical transplants of organs from donors.
- Free-Flap Surgeries: Surgical methods to reposition tissue.
- Stem Cell Treatment: Potential to regenerate or replace damaged tissues or organs.

Examples of Prostheses

Artificial Limbs: Such as arms and hands.
Dialysis Machine: Acts as an artificial kidney.
Cochlear Implant: Serves as an artificial ear.
Artificial Joints: Example includes hip joints.
Contact Lenses: Corrects vision.
Insulin Infusion Device: Acts similarly to an artificial pancreas.
Pacemaker: Regulates heart rhythms.
Artificial Heart Pumps: Specifically designed to aid or replace heart function.

Questions?

Assistance and clarification questions welcome.