describe cutaneous membrane
-it is your skin
-contains the epidermis attached to a thick layer of connective tissue (dermis).
-always exposed to the air and therefore considered a dry membrane.
describe serous membrane
-moist membranes found in closed ventral body cavities
-They have a visceral (inner) layer and a parietal (outer) layer separated by serous fluid.
what is a membrane?
-body lining that contains two or more tissue types
-an epithelium attached to a connective tissue proper
describe mucous membranes
-line all of the body cavities that open to the outside of the body the digestive, respiratory, and urogenital tracts
-adapted for absorption and secretion except the urogenital tracts
-produce large amounts of mucus.
Why are connective tissue proper, blood, bone, and cartilage all considered "connective tissue"?
-originates from embryonic Mesenchyme that can turn into blood, bone, connective tissue proper, or cartilage
describe endocrine gland
-lose their ducts during development
-produce hormones that are secreted through exocytosis into extracellular space
-hormones enter the blood or lymphatic fluid and are then able to travel to the body’s organs.
describe exocrine gland
-secrete their products onto body surfaces like the skin or into body cavities
-retain connecting cells which forms ducts able to transport secretions to the epithelial surface.
what are the steps of tissue repair?
inflammation
organization
regeneration or fibrosis
describe the first step of tissue repair
inflammation
-trauma to tissues releases inflammatory chemicals.
-chemicals make blood vessels leaky allowing white blood cells, fluid clotting proteins, and other plasma proteins to enter the injured area
-clotting seals off the injured area to prevent the spread of bacteria and toxins to the area
-clot exposed to air, dries and ultimately forms a scab
describe the second step of tissue repair
-organization
-clot is replaced by ingrowth of fragile capillaries from granulation tissue (delicate capillary tissue)
-this restores the vascular supply
-Fibroblasts mitosis and produce growth factors as well as collagen fibers to bridge the gap
-healing completes
-the fibroblasts revert back into fibrocytes or undergo apoptosis (cell death)
-Macrophages phagocytize dead cells and other debris
-surface epithelial cells multiply and begin to migrate over the granulation tissue.
describe the third step of tissue repair
-regeneration or fibrosis
-fibrosed area contracts pulling the margins of the wound together
-regenerates
-epithelium thickens under the scab which causes the scab to detach
-fully regenerated epithelium
-underlying connective tissue replaced with dense scar tissue
-A scar may be visible as a white line depending on the severity of the wound.
which tissues regenerative extremely well?
-Epithelial tissues
-bone
-areolar connective tissue
-dense irregular connective tissue
-blood-forming tissue
which tissues regenerate moderately?
-Smooth muscle
-dense regular connective tissue
which tissues have weak regeneration?
-skeletal muscle
-cartilage
which tissues have virtually no functional regeneration?
-cardiac muscle
-nervous tissue
what are the special characteristics of epithelial tissue?
-polarity
-avascular but innervated
-specialized contacts
-supported by connective tissue
-regeneration in high capacity
describe the structure of a plasma membrane?
-semipermeable layer of phospholipids
-heads are hydrophilic
-tails are hydrophobic
-fluid environment dictates the direction they face
distinguish between an active transport process and a passive transport process
active transport processes require energy input directly from the cell
what is active transport?
-transport against the concentration gradient
-via carrier proteins
-requires ATP
what are microtubules
cytoskeleton organelle
-support the cell and give it shape
-involved in intracellular and extracellular movements
what are microfilaments
cytoskeleton organelle
-involved in muscle contraction and other types of intracellular movement
what are intermediate filaments
cytoskeleton organelle
-stable elements that compose the cytoskeleton and resist against mechanical forces
what are microvilli
cellular extensions that increase the surface area for absorption
what are cilia
cellular extensions that propel substances across the surface of the cell in coordinated unidirectional movement
describe the structure of the skin
epidermis
dermis
hypodermis
describe the epidermis
-epithelial cells
-outermost protective shield
-only vascularized portion of the skin
describe the dermis
-makes up the bulk of the skin
-mostly dense connective tissue
describe the hypodermis
-not part of the skin
-under the dermis
-protective functions
-mostly adipose and some areolar tissue
what is the deepest layer of the epidermis?
-stratum basale
-attached to the underlying dermis
-contains a single row of stem cells
-highly mitotic
-one daughter cell pushed up to begin specialization into becoming keratinocyte
what is the layer above the stratum basale?
-Stratum Spinosum
-several cell layers thick.
-spinelike extensions of its keratinocytes, artifacts created during tissue preparation due to the cell shrinking while holding tight at their many desmosomes.
-contain thick bundles of intermediate filaments which consist of tension-resisting protein or pre-keratin
-This layer also contains the most amount of dendritic cells.
what are desmosomes
-anchoring junctions
-comprised of intracellular plaque and extracellular linker proteins
-linker proteins bind adjacent cells like velcro
-allow cells to withstand tension
-found in skin and heart
what are tight junctions
-integral proteins in the plasma membrane
-impermeable junctions
-attach adjacent cells
-prevent most molecules from passing between cells
-keeps digestive enzymes inside intestines
what are gap junctions
-communicating junctions
-filled with water
-connected by hollow protein cylinders called connexons
-serve as channels for transport
-found in electrically excitable tissues where ion passages allow coordination of electrical activity & contraction
-heart and smooth muscle
what is the epidermis layer beneath the stratum corneum
-Stratum Granulosum
-thin and only consists of 1 to 5 cell layers where the process of keratinization begins
-cells flatten with their nuclei and organelles disintegrating and accumulate two types of granules.
-Keratohyalin granules help form keratin in the upper layers.
-Lamellar granules contain water-resistant glycolipids that is secreted into extracellular space, combined with tight junctions aid in slowing water loss from the epidermis.
what is the layer below the stratum lucidum?
-Stratum Corneum
-outermost epidermal layer 20 to 30 cells thick and accounts for up to three-quarters of the epidermal thickness
-The cells in this layer are dead and keratinized
-glycolipids in extracellular space that keep this layer nearly waterproof.
what is the Stratum Lucidum
-found only in the thick skin of the epidermis
-visible through a light microscope as a thin translucent band
-Its cells are identical to those at the bottom of the stratum corneum
what are keratinocytes?
-Most of the cells in the epidermis
-role is to produce keratin, a fibrous protein that helps give the epidermis its protective properties
-arise from the Stratum Basale
-undergo an almost continuous mitosis that propels the newer cells upwards while also making the keratin that fills them
-when the cells approach the surface they are dead, scale-like flat sacs completely filled with keratin.
what are melanocytes?
-spider-shaped epithelial cells that are found in the Stratum Basale
-synthesize the pigment melanin
what are Dendritic Cells?
-Langerhans cells
-arise from bone marrow and migrate to the epidermis
-They ingest foreign substances and are key activators of our immune system. -slender processes extend around the keratinocytes forming a continuous network.
what are tactile epithelial cells?
-merkel cells
-present at the epidermal-dermal junction
-shaped like a spiky hemisphere
-associated with a disc-like sensory nerve ending
-The combination functions as a sensory receptor for touch.
what are the four sweat glands?
eccrine
apocrine
ceruminous
mammary
what are eccrine glands?
-abundant on palm, soles, forehead
-exocrine gland that secretes sweat
what are apocrine glands
-begin function at puberty due to androgens
-thought to play a role in pheromones
-found in axillary area (armpit)
what are ceruminous glands?
-found in lining of external ear canal
-secretion mixes with sebum to produce wax
what are sebaceous glands?
-oil glands found all over the body
-produces sebum
-sebum softens and lubricates hair and skin, and is bactericidal
what are arrector pili?
-smooth muscle cells
-forces sebum out of hair follicles
-responsible for goosebumps over fear or cold
what are nails?
-scale-like modifications of the epidermis
-contains hard keratin
-rich capillary beds underneath
what are the functions of the integumentary system?
Protection
Body temperature regulation.
Cutaneous sensation
Metabolic functions
Blood reservoir
Excretion
what are Langerhans cells?
a type of dendritic cells
describe the principle of complementary structure and function
what a structure can do depends on its form, structure and form are inseparable
define metabolism
"state of change" including all of the chemical reactions within cells
what is cellular respiration?
using nutrients and oxygen to produce ATP
what are the necessary life functions?
Maintaining boundaries
Movement
Metabolism
Excretion
Responsiveness
Growth
Reproduction
Digestion
what is the goal of the body systems?
maintaining life
what is homeostasis?
the body's ability to maintain a relatively stable internal condition amidst a continually changing outside environment
what is dynamic equilibrium
balance where internal conditions vary responsively within narrow limits
what is negative feedback?
-output shuts off or reduces intensity of original stimulus
-causes variable to change back in direction of the "ideal" state
-regulation of blood glucose
what is positive feedback?
-response enhances original stimulus that output is accelerated
-events are self-perpetuating "cascades"
-rare for homeostasis
-blood clotting
where do most diseases result from?
-disturbance of homeostasis
-homeostatic imbalance
what is the basic structure of a composite cell?
-plasma membrane
-cytoplasm
-nucleus
what are integral proteins?
-protein responsible for membrane functions
-firmly secured in lipid bilayer
-used in facilitated diffusion
what are peripheral proteins?
-protein responsible for membrane functions
-attach loosely to integral proteins or lipids
what is the glycocalyx?
-carbohydrate layer on cell surface
-acts as a thumbprint for each cell to differentiate them
how can substances pass through the membrane?
-membranes are selectively permeable
-passive process
-active process
what are the types of passive processes?
-simple diffusion
-facilitated diffusion
-osmosis
-filtration
what are the types of active processes?
-active transport
-vesicular transport
what is vesicular transport?
-active process
-transport across plasma or intracellular membranes via membrane-bound vesicles
what is the difference between exocytosis and endocytosis?
-exocytosis is the movement from the interior to the exterior of the cell
-endocytosis is the movement from the exterior to the interior of the cell
what is phagocytosis?
-solid material engulfed by the cell
what is pinocytosis?
-extracellular fluid containing dissolved molecules engulfed by cell
why do we need membrane junctions?
-some cells move around the body
-cells need membrane junctions to hold them in place
what are inclusions?
-chemical substances like nutrients
-may not be present depending on cell type
are ribosomes membranous organelles?
-nah
what are the cytoskeletal organelles?
-intermediate filaments
-microfilaments
-microtubules
-centrioles
what composes the integumentary system?
-hair
-skin
-nails
-sweat/oil glands
what are merkel cells?
-tactile epithelial cells
-present at the epidermal-dermal junction
-shaped like a spiky hemisphere
-associated with a disc-like sensory nerve ending
-The combination functions as a sensory receptor for touch.
where do you find thick skin and what layer is present there?
-palms, fingertips, soles of feet
-stratum lucidum
what contributes to skin color?
-three pigments
-carotene (yellow/orange)
-melanin (brown/black)
-hemoglobin (pink/red)
what are skin appendages?
-derived from the dermis
-help to maintain homeostasis
-hair and hair follicles
-sebaceous glands
-sweat, ceruminous, apocrine, and mammary glands
-nails
how does the cartilage get nutrients
perichondrium
what composes the axial skeleton
-skull
-vertebrae
-ribs
what composes the appendicular skeleton?
-upper and lower limbs
-shoulders
-hips
-scapula
long bones
-shaft
-2 ends
-prominent in limbs
flat bones
-thin, flat, maybe curved
-sternum
short bones
-cube shaped
-in wrist and ankle
sesamoid bones
-short bone formed in tendon (patella)
irregular bone
-vertebrae
what are the functions of bones
support
protection
movement
mineral and growth factor storage (calcium bank)
blood cell formation (hematopoiesis)
describe the structure of a long bone
- Diaphysis/tubular shaft Thick outer layer made ofcompact bone-->Central medullary/marrow cavity contains fat (yellow marrow)
inadults-Epiphyses = bone ends--->Outer compact bone/Inner spongy bone
------------------------------------------->Joint surface covered with (hyaline) articularcartilage
--->Metaphysis = where diaphysis &epiphysis meet
------------------->Epiphyseal line = between diaphysis & epiphysis – remnant of epiphyseal plate (hyaline cartilage disc that grows in children to ↑ bone length & overall height
(needs cartilage at the plate for growth)
what is the periosteum?
OUTSIDE BONE
-double membrane on outer surface except joint space
-outer fibrous layer is dense irregular CT
-inner layer is cells
what is the endosteum?
INSIDE BONE
covers trabeculae and lines canals through compact bone
-made of CT, osteoblasts, osteoclasts
what does hematopoiesis form?
all blood cells including plasma and white blood cells
what does the Rough ER send
-sends proteins to the golgi apparatus
-ribosomes located on the ER for efficiency
why is there cilia in the trachea
-the mucus traps foreign particles
-cilia moves the mucus through the trachea ciliated action
-expel or swallow
how does the epithelia get nutrients?
diffusion through the deeper dermis
what are osteoblasts?
-bone matrix synthesizing cell
what are osteoclasts?
-bone reabsorbing cell