Module 6 Flashcards
What are the basic cellular functions
-growth
-reproduction
-metabolism
requirements for cellular function
-bring in nutrients and expel wastes
-create cellular energy
-synthesize new proteins
-respond to external signals
-transport materials throughout the cell body
Epithelial cells
-form protective barriers in tissues and may be specialized to absorb or secrete specific compounds
Muscle cells
-responsible for movement of skeleton, heart, and many internal organs (stomach)
-specialized structure and proteins that allow to generate motion
nerve cells
-conduct electrical signal throughout body
-control contraction of muscles
-responsible for senses, taste, touch, smell, sight and hearing
connective tissue cells
-create extracellular material that holds cell together in tissue
-may be specialized to absorb or resist external forces (ex. tendons, vertebral discs)
bone cells
-form bones of skeletal system that give strength and support body
-include osteoclast cells that degrade bone and osteoclast cells that create bone
secretory cells
-form glands and secrete substances (ex. mucous, hormones, enzymes)
adipose cells
-located throughout body to store fat in form of triglycerides which released when body fasting
red blood cells
-form primarily in bone marrow and released into circulation where move and deliver oxygen throughout body
organism hierarchy triangle (top to bottom order)
organism
body systems
organs
tissues
cells
cell junction -> allows for organs and tissues to form
-type of membrane protein which facilitates cell-to-cell attachments
-that allows for communication and barrier format
-endothelial cells (lines inside of blood vessels and act as barrier) and epithelial cells (line cavities and surface of organs like inside digestive tract and rest on basement of membrane which is specialized ECM that separates epithelial cells from underlying connective tissue) which form tight networks to keep unwanted material from moving from one side of cell layers to another
-those cells require specialized adhesion proteins called junction complexes
Proteins in junctional complex
-epithelial and endothelial cells form cell-to-cell junctions known as these
involves
Tight junctions
-structurally and functionally divide plasma membrane into 2 domains
-apical (top) surface of cell
-basal (bottom) surface of cell
-phospholipids can not move across them
-regulate paracellular transport (transport of material between cells)
Adherens Junctions
-use transmembrane receptor proteins called cadherins that bind to other cadherins on neighbouring cells
-amount of overlap between neighbouring cadherins proprotional to bond strength between them
-found in neural synapses and cardiac muscle cells
-actin bundles are adjacent to junction at cytoplasmic face of membrane and cadherins form rods between cells and linked to actin cytoskeleton by anchoring proteins like catenins
Desmosomes
-provide structural integrity to cell and function like “snap” in series with eachother
-link to cytoskeleton of cell
-found in cells exposed to physical strength like skin and cardiac muscle
-hemidesmosomes consist of 1/2 desmosome complex
- tether in basement membrane of epithelial cells, strongly attaching to extracellular matrix ECM
GAP JUNCTION NOT PART OF JUNCTIONAL COMPLEX
ECM
-extracellular matrix
-network of molecules that fill space between cells
-proteins located in this matrix formed by cells to provide external structure and support of the cell and tissues in the body
-without -> tissues unable to hold together
-basement membrane found below epithelial cells and on the outiside of tissue
-consists of a special sheet of collagen and other proteins that structural foundation and barrier for epithelial cells and network to stabilize tissues
Types of proteins in ECM to support function
collagen
-most prevalent protein
-main strucutral protein in ECM
-exists as triple helix, which crosslink to form fibrils
-fibrils form colagen fibres
- body makes multiple types of collagen that specific to different tissue types
fibronectin
-glycoproteins that connect cells to collagen matrices, functioning in cell adhension
-expressed as dimers, and bind to integrns, which type of cell surface protein
-interact with cytoskelton causes fibronectin dimers to straighten and associate with fibronectins
-results in fibrils at cell surface
Elastin
-giving elasticity to cells
-allow tissues to return back to original shape after being destroyed by extrnal force
-hydrophobic and hydrophilic regions, which facilitate ability of elastin proteins to return to original shapes after being stretched
Laminins
-provide adhensive substrate for cells
-strengthen ECM
-form triple helical coils
-forms cross-like structure
-multiple binding sites for ECM proteins
-each “t” or “cross” form conneection with neighbouring molecules
-in this way, laminin can handle tension in multiple directions
-form web-like networks that have great deal of strength in multiple directions
-25 nm
Proteoglycans
-hydrated gel that resistant to compressive forces
-critical for structures like cartilage in our joints
-consists of a protein polypeptide core and attached sugar residues
-complementary to structural proteins (like collagen and elastin) of ECM
Cells come together to form what four major tissue groups
Epithelial tissues
-play critical roles in body
-anything entering body cross this protective layer
-exchange not same for all epithelial tissues, specialization
epithelial tissues in skin
-skin made of several types of epithelial, examples like squamous, cuboidal and columar which that have different structures like simple, stratefied or pseudostrafied
epithelial tissues in glands
-cells organize to form picket-like structures which release secretions via ducts
exocrine gland -> release secretions to outside of body ex. sweat glands
endocrine glands -> release their secretions (hormones) internally into bloodstream
-dont have ducts as release products directly into blood
epithelial tissues in digestive tract
-specialized for absorption, secretion and protection
-line entire digestive system from mouth to anus
-many different epithelial cells found throughout
if using stomach as ex. three different types of epithelial tissues: those that produce and extrete proteins, those that form digestive glands and those that are specialized for transportation
-produce and excrete proteins through process of exocytosis, glycosylated proteins, these proteins form layer of mucus that protects epithelial cells from themselves and acidic enviroment
-form digestive glands that produce and release both enzyme proteins and hydrochloric acid that breaks down food. considered exocrine gland as lumen considered external to the body
-facilitate transportation. exs found in digestive system where nutrients transported across epithelial cell layers to enter body. In kidney, ions and water transported across epithelial cell layers to remove waste and regulate urine volume
define tissue
-groups of cells which not necessarily identical but collectively carry out specific function
nervous tissues
-composed of highly specialized cells that use electrical communication to carry information over long distances in body
-these tissues compsoed of nerve cells, and glial cells including Schwann cells that serve a supportitve role
How nervous tissues work
–cells tighly control internal enviroment resulting in different concentrations of ions inside and outside cell
-as ions change-> create electronical potential
-change in electronical potential singals (which very fast) to allow for rapid communication throughout the body (ex. hand touching hot stove)
Muscle tissues
-convert chemical and electrical signals into mechanical movement
-compressed of cells that specialize in contraction
-muscle cells rich in actin-myosin networks, since cells responsible for contracting and generating force
3 types:
skeletal muscle-repsonsible for moving skeleton
smooth muscle-lines most of digestive system, the larger blood vessels and anywhere in the body that requires contractile activity
-cardiac muscle- found only in heart adn organized to pump blood throughout the body
actin
-promient cytoskeletal protein that along with protein myosin, generates movement within the cell
connective tissue
-do so outside of cell and fill space between all of the other cells to provide mechanical strength and cushioning
-make up large component of ECM, cells that make ECM
-types characterised by ECM. ex. lungs have alot of moveent, ECM rich in elastin. Bone ECM rigid to provide strength. Another ex. fiberblast
Organs
-another level of organization
-structures where two or more tissues
ex. stomach organ which stores, breaks down, digests food, and has multiple layers of tissues
contains tissues:
epithelial tissues- prtoect the underlying layers from digestive proteins and acids by epitheial cells
muscle tissues- under epithelial cells adn outside stomach is lined with layers of smooth muscle cells
-rhythmically contract both mix the stomach contents adn help propel them into intensines
Nervous tissues-control and corrdinate miscle contracts and some gland secretion
connective tissues- hold everything together and provide shape to the stomach
-altogether -> create organ
Body systems
-formed when two or more organs come together with a coordinated purpose
-11 body systems in total (12 diagrams to differentiate between male and female
ex. cardiovascular system
-compressed of heart, blood vessels and blood
