A state of equilibrium or balance in the body internal environment maintained by compensating for charges ( feedback and regulation )
Groups of similar cells that work together to perform a special function
There are four basic types of tissue:
Connective: supports and connects all parts of body; includes adipose (fat), cartilage, bone and blood
Epithelial: covers and protects body and mind organs, vessels, and cavities
Muscles: contracts to produce movement
Nerve: Nerve tissue is specialized for intercellular communication by the conduction of electrical impulses and release of chemical messages.
The skeletal system includes all the bones, plus the connective tissue at the joints. It functions to support the body, provide movement, and protect
the internal organs. Bones also store the minerals phosphorus and calcium, and the marrow of certain bones is the site of hematopoiesis, formation of
Bones: Type of defense connective tissue which consists of bone cells surrounded by hard deposits of calcium salts.
Bone is living tissues with their own network of blood and lymph vessels and nerves, There are 206 bones in the adult skeleton. Bones are classified by their shapes:
Flat ( ribs )
Irregular ( vertebrae )
Long ( femur )
- Short (carpals )
Joints: Junction or union between two or more bones
Freely movable joints have synovial cavity
Moves body ( via contraction of muscles cells )
Maintains posture ( via muscles tone )
Produces heat ( from muscle cell metabolism )
Aids in organ function and blood circulation
Skeletal muscles move the skeleton, allowing the vast range of activities that make up daily life. Cardiac muscle pumps the blood for the circulatory system. The primary function of smooth muscle is to regulate the passage of materials through vessels.
Cardiac muscles: Walls and layers of the heart; used pump blood
Skeletal muscles: attach to bones; produces movement and joints
Smooth muscles: Wall of hollow organs; produces peristalsis
The integumentary system forms the outer covering of the body and includes the skin, hair, nails, and sweat glands. The principal functions of the integumentary system are protection, thermoregulation (control of body temperature), and sensation.
The skin forms an effective barrier against invasion by microbes and chemicals. Evaporation of sweat from the surface of the skin is the major means by which humans cool themselves.
Sensory cells embedded in the skin allow the brain to receive information about the environment.
Protect the body from bacterial invasion, dehydration, sun rays
Regulate body temperature
Eliminates some waste through sweat
Received environmental stimuli ( heat, cold, touch, pain )
Epidermis: Outermost and thinnest later of the skin.
Avascular ( no blood vessels )
Produces skin pigment melanin
Dermis: Inner layer of the skin
Composed of elastic and fibrous connective tissue
Contains blood and lymph vessels oil and sweat glands
Subcutaneous: Connective and adipose tissue; Connects skin to surface muscles
Function is to control and coordinate activities of various body systems by electrical impulses and chemical substances sent and received
Somatic: voluntary movement of skeletal muscle
Autonomic: involuntary movement of cardiac and smooth muscles
Central nervous system ( CNS )
Brain and spinal cord
Surrounded and cushioned by cavity filled with cerebrospinal fluid
Protected by three layers of connective tissue
Sensory or afferent nerves: Carry impulses to CNS From sensory receptors in various parts of the body
Motor or efferent nerves: Carry impulses from CNS to organs, glands and muscles
The digestive system is responsible for the absorption of nutrients into and the elimination of waste from the digestive tract.
The digestive system includes the mouth, esophagus, stomach, small and large intestines, rectum, and anus, plus the accessory digestive organs, including the liver, gallbladder, and pancreas.
The purpose of digestion is to break down food into molecules small enough to be absorbed by the intestines. This process includes both mechanical and chemical digestion.
Take in food
Brake food down into usable components for absorption
Eliminate waste products
Gastrointestinal tract: ( mouth, pharynx, esophagus, stomach, small and large intestine )