Module 6

Question 1

What are the basic cellular functions

Answer 1

-growth
-reproduction
-metabolism

Question 2

requirements for cellular function

Answer 2

-bring in nutrients and expel wastes
-create cellular energy
-synthesize new proteins
-respond to external signals
-transport materials throughout the cell body

Question 3

Epithelial cells

Answer 3

-form protective barriers in tissues and may be specialized to absorb or secrete specific compounds

Question 4

Muscle cells

Answer 4

-responsible for movement of skeleton, heart, and many internal organs (stomach)
-specialized structure and proteins that allow to generate motion

Question 5

nerve cells

Answer 5

-conduct electrical signal throughout body
-control contraction of muscles
-responsible for senses, taste, touch, smell, sight and hearing

Question 6

connective tissue cells

Answer 6

-create extracellular material that holds cell together in tissue
-may be specialized to absorb or resist external forces (ex. tendons, vertebral discs)

Question 7

bone cells

Answer 7

-form bones of skeletal system that give strength and support body
-include osteoclast cells that degrade bone and osteoclast cells that create bone

Question 8

secretory cells

Answer 8

-form glands and secrete substances (ex. mucous, hormones, enzymes)

Question 9

adipose cells

Answer 9

-located throughout body to store fat in form of triglycerides which released when body fasting

Question 10

red blood cells

Answer 10

-form primarily in bone marrow and released into circulation where move and deliver oxygen throughout body

Question 11

organism hierarchy triangle (top to bottom order)

Answer 11

organism
body systems
organs
tissues
cells

Question 12

cell junction -> allows for organs and tissues to form

Answer 12

-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

Question 13

Proteins in junctional complex

Answer 13

-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

Question 14

ECM

Answer 14

-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

Question 15

Types of proteins in ECM to support function

Answer 15

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

Question 16

Cells come together to form what four major tissue groups

Answer 16

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

Question 17

define tissue

Answer 17

-groups of cells which not necessarily identical but collectively carry out specific function

Question 18

nervous tissues

Answer 18

-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

Question 19

How nervous tissues work

Answer 19

–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)

Question 20

Muscle tissues

Answer 20

-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

Question 21

actin

Answer 21

-promient cytoskeletal protein that along with protein myosin, generates movement within the cell

Question 22

connective tissue

Answer 22

-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

Question 23

Organs

Answer 23

-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

Question 24

Body systems

Answer 24

-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

Question 25

organisms

Answer 25

-final level of organization
-all cells come together to work to organize and carry out life-sustaining systems

Question 26

Homeostasis

Answer 26

-ability of cell or organism to regulate and maintain its internal enviroment, regardless of influences of external enviroment
-do counter changesto maintain this

Question 27

homeostatic control system

Answer 27

-maintaining a set of points requires this
-3 componentents

1. sensor-detects enviromental change
2. integrators- compares variables value to its set point
3. effector- if value different from the set points, effector initiates changes to restore the set point
   ex. body temperature
   set point: 36-38 degrees celcius
   sensor: temperature-monitoring nerve cells sense temperature adn send that information to thermoregulation center
   Integrator: thermoregulation centre takes information from sensor adn compares to set point. if differnce, thermoregulation center send singals to effector
   Effector: integrator causes blood vessels in skin to constrict, minimizing heat loss and skeletal muscle rapidly contract, causing shivering, which generates heat

Question 28

Intrinsically and extrinsically controlled

Answer 28

homeostatis grouped into one of the 2

Intrinsically controlled
-aka local control
-sensor, integrator and effector of system all located in tissue, such that tissue can regulate own internal enviroment

extrinsically controlled
-regulatory mechanism outisde tissue or organ, in such case of body temperature regulation
-majority of homeostatis