Organ Systems and Their Functions

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Organ Systems and their functions
I. Integumentary System
Functions to protects against environmental hazards; helps control body temperature. Composed of Skin and derivates Epidermis – covers surface; protects deeper tissues Keratinocytes – waterproofing Melanocytes – pigment –protects against UV light Dermis – Nourishes epidermis; provides strength; contains exocrine glands Collagenous tissue – strength Skin Derivates A. Hair– protection and warmth (vellus – fine un-pigmented hair: terminal hair – course and pigmented) B. Sebaceous Glands – Secrete oily substance that lubricates hair shaft and water proofs the epidermis C. Sweat Glands – Produce perspiration for evaporative cooling D. Nails – Protect and stiffen distal tips of digits E. Sensory Receptors – Provide sensations of touch, pressure, temperature, pain Subcutaneous Layer – Stores lipids; attaches skin to deeper structures; cushions underlying tissues

II. Skeletal System (206 bones)
Functions to provides support; protects tissues; stores minerals; forms blood Composed of bones, cartilages, and Joints Axial Skeleton (80 bones) - skull, vertebrae, ribs, sternum, sacrum Protects brain, spinal cord, sense organs, and soft tissues of thoracic cavity; supports the body weight over the lower limbs Appendicular Skeleton (126 bones) - bones and girdles of the limbs, hands and feet Provides internal support and positioning of the limbs; supports and moves axial skeleton Bone Marrow – Acts as primary site of blood cell production (red blood cells, white blood cells); stores lipid reserves and mineral storage Epiphyseal plate – growth plate We have 500 bones when we are born but these fuse in the adults into 206 bones. Lever Systems (Fulcrum –pivot; load – weight; effort – force) 1st Class – fulcrum in the middle 2nd Class - effort in the middle 3rd Class - load in the middle Ligaments attach bone to bone

III. Muscular System (600 muscles)
Functions to produces movement and locomotion; provides support; generates heat Skeletal Muscle – striated, multinucleated, voluntary attached to the skeleton by tendons Work in pairs (antagonistic muscles) one muscle contracts the other relaxes Requires ATP to contract and relax. They store glycogen, oxygen, and calcium Exercise increases the number of proteins in the cytoskeleton, vascularity, glycogen storage, and oxygen storage. Increases the amount of time spend in aerobic respirations (endurance)

IV. Nervous System
Functions to control body movements and functions; memory; and monitors internal and external environment. Directs immediate response to stimuli, usually by coordinating the activities of other organ systems Composed of brain, spinal cord, and nerves Central Nervous System (CNS) – Acts as control center for nervous system; processes information; provides short-term control over activities of other systems A. Brain – Performs complex integrative function; controls both voluntary and automatic activities B. Spinal Cord – Relays information to and from brain; performs less-complex integrative functions; directs many simple involuntary activities Peripheral Nervous System (PNS) – Links CNS with other systems and with sense organs A. Efferent nervous system – Motor neurons B. Afferent nervous system – sensory neurons Neurons - nerve cells communicate by neurotransmitters Sympathetic – fight or flight response Parasympathetic – returns the body to rest. Stroke – interruption in the blood supply to the brain

V. Endocrine System
Functions to control body functions through chemical messengers called hormones Directs long term changes in other organs Organs A. Hypothalamus – master gland – controls the pituitary gland B. Pituitary Gland – master gland also. It controls other endocrine glands; regulates growth and fluid balance Growth hormone, (GH) Thyroid stimulating hormone (TSH) Follicle stimulating hormone (FSH) – gonads Prolactin – mammary glands C. Thyroid Gland – Controls...
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