BIO 197 final exam
homeostasis
the existence of a stable internal environment, which is vital for our survival.
Systems respond to external and internal changes to keep variables within normal
ranges (body temperature, fluid balance, etc)
chemical level:
atoms are the smallest unit of matter, which form molecules
cellular level:
cells are the smallest units in the body, often made up of a nucleus and organelles
formed by complex molecules
tissue level:
tissues are a group of cells working together to perform particular functions
organ level:
organs are made of tow or more tissues to perform a particular function
organ systems level:
organ systems are a group of organs working together to accomplish a larger goal
organism level:
the organism, human beings, is the individual life form and highest level of
organization we consider
What is the organization of anatomy? (cell to organ systems)
anterior
most forward
posterior
toward the backside
superior
higher up on the body in comparison
inferior
lower on the body in comparison
medial
closer to the midline
lateral
away from midline
proximal
near the trunk
distal
away from the trunk
,-protection
-storage of lipids
-synthesis of vitamin D3
-thermoregulation
-sensory information
-coordination of immune system
-excretion of lipids via sebum
what are the functions of the integumentary system?
thin skin
composed of 4 epidermal layers: stratum basale, stratum spinosum, stratum
granulosum, and stratum corneum
thick skin
found on the palms of our hands and soles of our feet, contains stratum lucid as an
extra layer between the stratum granulosum and stratum corneum
stratum corneum
-exposed surface of skin, water-resistant not waterproof
-15-30 layers of keratinized cells
-new cells move from stratum basale to stratum corneum in 7 to 10 days
-exposed cells are shed after 2 weeks
stratum lucidum
-thick skin only
-covers the stratum granulosum
stratum granulosum
-three to five layers of keratinocytes
-produced from cells of stratum spinosum
-most cells stop dividing and produce keratin
-forms dense granules
-promotes cellular dehydration and cross linking of keratin fibers
-after production of proteins, cells die
-last living layer of cells
stratum spinosum
-eight to then layers of keratinocytes bound by desmosomes
-cells appear shiny in histological sections
-produced by division of cells in stratum basale, some of which continue dividing
-contains dendritic cells, active in immune response
stratum basale
-attached to basement membrane by hemidesmosomes
-forms a strong bond between epidermis and dermis
-contains epidermal ridges that lie next to dermal papillae in dermis
-has many stem-like cells that give rise to other epidermal layers
dermis
consists of areolar connective tissue, has capillaries, lymphatic vessels, and sensory
neurons
dermal papilla
, -specialized mesenchymal cells located at the bottom of hair follicles
-play a pivotal role in hair formation, growth, and cycling
reticular layer of dermis
consists of dense irregular connective tissue, contains collagen and elastin fibers
collagen fibers
gives the dermis its strength and resists stretching
elastin fibers
help skin retract when stretched, when skin is stretched beyond its limits, it wrinkles
and creases creating stretch marks
melanin
primary skin and hair color determinant, produced by melanocytes in the Stratum
Basale
sebaceous glands
-produce sebum
-associated with hair follicles
-discharge an oily lipid secretion onto hair follicles, protects from bacterial growth
and lubricates hair and skin
apocrine sweat glands
-what we typically think of when we refer to sweat glands
-start to function after puberty as they are influence by hormones, associated with
hair
-they form in axillary, pubic, and perineal regions around the areola of nipples
eccrine sweat glands
-located on the skin throughout most of the body
-the central cells of the developing ducts degenerates to form a lumen
-these sweat glands function shortly after birth
epithelia
-covers exposed surfaces, lines internal passageways, and forms glands
-layers of cells that cover external or line internal surfaces for protection
-physical protection
-permeability control
-provide sensation
-produce specialized secretions
functions of epithelium:
-skin
-lining of digestive, reproductive, and urinary tracts
-lining of the lungs
-glands
where is epithelium located in the body?
apical
facing the external environment or internal space
avascular:
without vessels or lacking blood vessels
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