Structural Organization of the Body and Organ Systems
Structural Organization of the Body
Tissues
Tissues are composed of cells grouped by size, shape, and function. There are four main types of tissues in the human body:
- Epithelial
- Connective
- Muscle
- Nervous
Epithelial Tissue
- Forms the skin, covering the outside of the body.
- Lines the inside of the body.
- Membranes are formed by two thin layers of tissue.
- Cells may secrete fluids.
Connective Tissue
Connective tissue supports and connects organs and other tissues.
- Adipose tissue stores fat cells.
- Cartilage provides firm, flexible support, forming the embryonic skeleton and parts of the adult skeleton.
- Tendons are white bands of connective tissue that attach skeletal muscle to bone.
- Ligaments are strong, flexible bands of connective tissue that hold bones firmly together at the joints.
Muscle Tissue
Muscle tissue contracts to produce movement. There are three types of muscle tissue:
- Cardiac: Striated and involuntary, contracts the heart.
- Skeletal: Striated and voluntary, attached to the skeleton.
- Smooth: Non-striated and involuntary, provides movement in various body systems.
Nervous Tissue
Nervous tissue reacts to stimulation and conducts electrical impulses.
Organ Systems
Skeletal System
The skeletal system provides support, protection, and movement. Key components include:
- Skull
- Ribs
- Pelvis
- Humerus
- Femur
Muscular System
The muscular system provides support, protection, movement, and generates heat. Key muscles include:
- Diaphragm
- Pectoralis Major
- Gluteus Maximus
Circulatory System
The circulatory system pumps blood and transports oxygen. Key components include:
- Blood
- Arteries
- Veins
- Heart
Lymphatic System
The lymphatic system stimulates immune response and produces lymphocytes. Key organs include:
- Spleen
- Tonsils
- Thymus Gland
Respiratory System
The respiratory system facilitates the exchange of oxygen and carbon dioxide. Key components include:
- Lungs
- Diaphragm
- Alveoli
- Larynx
- Pharynx
Digestive System
The digestive system digests food and absorbs nutrients. Key organs include:
- Esophagus
- Stomach
- Liver
- Large Intestine
- Small Intestine
Integumentary System
The integumentary system protects, regulates body temperature, and provides sensation. Key components include:
- Skin
- Hair
- Sweat Glands
Nervous System
The nervous system processes information. Key components include:
- Brain
- Spinal Cord
Sensory System
The sensory system provides sensation through:
- Eyes
- Ears
- Nose
- Mouth
- Skin
Urinary System
The urinary system allows for the elimination of urine. Key organs include:
- Kidneys
- Bladder
Endocrine System
The endocrine system controls body functions through hormones. Key glands include:
- Pancreas
- Thyroid Gland
- Pituitary gland
- Adrenal gland
- Pineal gland
- Testis (male)
- Ovary (female)
Reproductive System
The reproductive system controls reproductive processes. Key organs include:
- Females:
- Uterus
- Ovaries
- Vagina
- Males:
- Testes