Module 6 Flashcards
organism hierarchy
cells
tissue
organs
body systems
organisms
cell junctions
type of membrane protein facilitating cell to cell attachments
endothelial cells
cells that line the inside of blood vessels
protective barrier
epithelial cells
cells that line the cavities and surfaces of organs
rest on basement membrane (specialized extracellular matrix that separates them from connective tissue)
types of junction proteins
tight junctions
adherens junctions
desmosomes
all part of junctional complex
tight junctions
structurally and functionally dived the plasma membrane into two domains (apical surface - top, basal surface - bottom)
phospholipids cant move across tight junctions
proteins in tight junction connect to cell cytoskeleton
regulate paracellular transport
adherens junctions
use transmembrane receptor proteins (cadherins) that bind to other cadherins on neighbouring cells
overlap of cadherins is proportional to bond strength
found in neural synapses and cardiac muscles
desmosomes
provide structural integrity to cell
function like snaps to eachother
link cytoskeleton of cell
found in cells exposes to physical stress (skin and cardiac muscles)
gap junctions
built of two halves, connect to cross intercellular gap
cells connected by gap junctions use channel gating to move ions sugars nucleotides and other molecules
important in cardiac muscles contraction
extracellular matrix (ECM)
network of molecules that fill space between cells
proteins formed by cells to provide external structure and support of the cells and tissues of the body
without tissues cant hold together properly
basement membrane
special matrix below epithelial cells and on outside of tissues
consist of special sheet of collagen and other proteins that is a structure foundation and barrier for epithelial cells and a network to stabilize tissue
types of ECM proteins
collagen
fibronectin
elastin
laminins
proteoglycans
collagen
main structural protein of ECM
exists as triple helix which crosslink to form fibrils which form collagen fibers
multiple types specific to different tissues
fibronectin
glycoproteins that connect cells to collagen matrices, cell adhesion
expressed as dimers and bind to integrins
interactions with cytoskeleton cause dimers to straighten and associate with other fibronectins resulting in fibrils at the cell surface
elastin
give elasticity to tissues allowing them to return back to original shape after being distorted by external force
have hydrophobic and hydrophilic regions allowing them to return
laminins
provide adhesive substrate for cells and strengthen ECM
forms triple helical coils, forms cross like structure w multiple binding sites for ECM proteins
each end of T forms a connection with neighbouring molecule
can handle tension in multiple directions
proteoglycans
hydrated gel resistant to compressive forces
important for cartilage in joints
consist of protein polypeptide core and attached sugar residues
types of tissues
epithelial
nervous
muscle
connective
epithelial tissues + types
protects inside of body from environment
there is specialization
- skin epithelial tissues
- gland epithelial tissue
- digestive tract epithelial tissue
gland epithelial tissue
epithelial cells specialize to form glands
cells organize forming pocket like structures where they release secretions via ducts
exocrine glands
- release secretion outside body
endocrine glands (dont have ducts)
- release secretions internally into bloodstream
digestive tract epithelial tissue
line entire digestive system
different types functions
- produce and excrete glycosylated proteins (exocytosis), mucus protecting cells
- form digestive glands that produce and release digestive enzymes and hydrochloric acid (exocrine gland)
- facilitate transportation, nutrients transport across cells to enter body
nervous tissues
use electrical communication to carry information over long distances
composed of nerve cells and glial cells
mechanisms of nervous tissues
differences in ion concentration across membrane creates electrical potential
changes in electrical potential are used as a signal allowing for rapid communication
muscle tissue
convert chemical and electrical signals into mechanical movement
types of muscles
- skeletal (moves skeleton)
- smooth (lines digestive system, larger blood vessels and anywhere requiring contractile activity)
- cardiac (found in heart, pump blood)
connective tissues
fill space between cells to provide mechanical strength and cushioning for protection
make up the ECM
different types with different characteristics
- lungs, ECM rich in elastin
- bone, ECM rigid
common cell type fibroblast
organs
when two or more tissue types come together to form a function
stomach
epithelial tissues line it, protect from digestive proteins and acids
outside lined with smooth muscles cells to contract to mix contents and propel them into the intestine
nervous tissues control and coordinate contractions and some gland secretion
connective tissue, hold everything together and provide shape
body systems
formed when two or more organs come together with a coordinated purpose (11 total)
cardiovascular system
heart (pump), blood vessels (routes of transport) and blood (carries nutrients to cells and removes their wastes)
homeostasis
ability of a cell of organism to regulate and maintain is internal environment regardless of the influences of the external environment
homeostatic control system
sensor - detects environmental variable
integrator - compares the variable to its set point
effector - if value is different from set point effector initiates changes to restore set point
can be intrinsically or extrinsically controlled
body temperature control
body set point 37 C
sensor - temperature monitoring nerve cells, always sensing and sending information to thermoregulation center
integrator - thermoregulation checks information and compares it to set point, if different signals effector
effector - blood vessels in the skin contract (minimize heat loss) and skeletal muscles rapidly contract, shivering (generate heat)
intrinsically controlled
sensor, integrator and effect all located within a tissue
exercising skeletal muscle that needs oxygen to produce ATP
- oxygen drops, sensed by blood vessels, muscles dilate to increase oxygen
extrinsically controlled
regulatory mechanisms outside of the tissue or organ
negative feedback loop
effect initiate response in opposite direction thus restoring set point
once reached effector actions stop
positive feedback loop
effector amplify initial signal
not homeostatic
breastfeeding stimulates more milk production
