BIO 2403 LAB Chapter 2 & 7
Terms
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- Epidermis
- composed of thick keratinized stratified squamous epithelial cells, outermost protective shield of the body that consisit of 4 cell types & 4 or 5 layers
- Dermis
- A tough leathery layer composed of fibrous connective tissue that makes up bulk of the skin. Vascularized nutrients reach the epidermis by diffusing thru the tissue fluid. Regulation of body temp. hot (arterioles-dilate); cold (arterioles-constict)
- Hypodermis
- aka superficial fascia - (subcutaneous tissue) consists mostly adipose
- 4 distinct cell types
- Keratinocytes, melancocytes, langerhans' cell (epidermal dendritic cells), merkel cells
- Keratinocytes
- Produces keratin fibrils, which arises from stratum basale layer. (a fibrous protein that gives the epidermins its protective properties)
- Melanocytes
- Provide protection for the keratinocyte nucleus by forming a pigment shield (melanin granules) that protects the nucleus from the damaging effects of ultraviolet (UV) radiation in sunlight. Freckles due to a concentration of melanin in one spot.
- Langerhans's cell
- Phagocytic (macrophage) cells play a role in immunity that arise from bone marrow.
- Merkel Cells
- form touch receptors; Merkel discs associated with sensory nerve ending at the epidermal-dermal junction.
- 5 Layers of epidermis
- Stratum corneum, lucidum, granulosum, spinosum, basale
- Stratum corneum
- horney layer, accounts for up to 3/4 of epidermal thickness (20-30 cell layers thick)
- Stratum lucidum
- clear layer, very thin translucent band with flattened, dead keratinocytes with indistinct boundaries, not present in regions if thin skin.
- Stratum granulosum
- granular layer, the cells contains an abundance of granules. Cells flatten, nuclei & organelles disintegrate due to inadequate nourshiment.
- Stratum spinosum*
- spiny or prickley layer, appear spiky and contain a weblike system of intermediate filaments made of prekeratine protein.
- Stratum basale*
- basal layer, constantly undergo mitotic cell division. (single cell layer) also known for tis alternate sname--stratum germinativum.
- *
- only layer to receive adequate nourshiment is spinosum & basale layers.
- 2 layers of dermis
- Papillary layer, reticular layer
- Papillary lyaer
- thin, superficial, heavily invested w/blood vessels contain free nerve endings (pain receptors) & Meissner's corpuscles (touch receptors). Fingerlike projections on its uperior surface.
- Reticular layer
- deepest layer, accounts for about 80% of dermis, typical dense irregular connective tissue.
- 2 Cutaneous glands
- Sweat (sudoriferous) glands, sebaceous glands
- Sweat (sudoriferous) glands
- distributed over the entire skin surface, except nippples and parts of external genitalia. Body's heat regulation controlled by nervous system
- Sebaceous glands
- found nearly all over the skin, except on palms, and soles of feet. Secret oily substacnes and fragemented cells or sebum. Glands are inactive during childhood and active druing puberty.
- Hairs or pili
- enclosed in hair follicules that are found over the entire body surface, ecept for thick skinned area.
- Nails
- hornlike or scalelike modifiaction of the epidermis that forms a clear protective covering, consist of several nammed parts.
- Nail parts
- proximal to distal: Nail matrix, root of nail, proximal/lateral nail fold, eponychium (cuticle), body of nail, nail bed, free edge of nail, phalanx, stratum germativum
- Cardiovascular system
- Heart pumps blood; heart, blood vessels, and blood.
- Endocrine system
- pancreas- regulats insulin and glucagon. Pituitary, thymus, thyroid, parathyroid, adrenal, and pineal glands; ovaries, testies, and pancreas
- Digestive system
- Esophagus- passageway for food to enter the stomach froum the mouth. Stomach- site where chemical breakdown of proteins begin and good is converted into chyme. Liver- produces bile and its main function is to filter & process nutrient-rich blood that's delivered to it. Small intestine- sute for nutrient absorption. Large intestines- absorption of water, and some electrolytes & defecation. Pancreas- contain pancreatic juices that produce enzymes that break down all categories of food. Gall bladder- a sac that stores and concentrates bile (bile-emulsifies fat)
- Urinary system
- Kidneys- major excretory organ. Regulates the volume and chemical makeup of blood, maintain pH, water & salt balance and removes the excess in the form of urine. Ureters- a tube that transports urine to the urinary bladder form the kidneys. Bladder, urethra
- Lymphatic system
- Spleen- site for lymphocyte proliferation & immune function; destroys aged or defective RBC's ; stores and releases the breakdown products of RBC's; stores platelets and site of erythrocyte production in the fetus. Lymphatic vessels, lymph nodes, thymus, tonsils, and catter lymphoid tissue.
- Respirator system
- Lungs- are air passageways/chambers that contain terminal air sacs (alveoli), which are the actual sites of gas exchange. Trachea- (tubelike windpipe) air passageway/chamber, where its terminal end is the actual site of gas exchange; warms & moistens incomming air. Diaphragm- a muscle that divides the body into thoracic & abdominopelvic cavities. Increases volume of the thoracic cavity when contracted (inhaling.) Nasal passages, pharynx, larynx, bronchi
- Skeletal system
- bones, cartiage, tendons, ligaments, and joints.
- Muscular system
- muscles attached to the skeleton
- Nervous system
- brain, spinal cord, nerves, and sensroy receptors.
- Reproductive system
- male / female.