Tissue Types and Membrane Transport

Question 1

Gap junctions

Answer 1

enable communications between cytoplasms of adjacent cells

connexin proteins

Question 2

tight junctions

Answer 2

adjacent cell membranes are partly fused together, making a barrier

claudin and occludin proteins

Question 3

anchoring junctions

Answer 3

anchor cells to each other or ECM. Cell-cell anchoring junction. Hesmidesmosomes anchor cells to ECM

provide strength when the tissue is under mechanical stress

cadherin proteins

Question 4

epithelial tissue function

Answer 4

protect the internal environment of the body and regulate exchange of materials between internal/external environment

minimal matrix, basal lamina

no direct blood supply

has microvilli and cilia

covers body surface lines cavities and hollow organs and tubes, secretory glands

variable number or layers, from one to many; cells flattened, cuboidal or columnar

Question 5

types of epithelial tissue

Answer 5

exchange, protective, ciliated, transporting, secretory

Question 6

connective tissue cells function

Answer 6

provides structural support and physical barriers
found within extensive extracellular matrix networks

matrix is varied - protein fibers in ground substance that ranges from liquid to gelatinous to firm to calcified

cartilege has no blood supply

supports skin and other organs

cells not in layers; usually scattered in matrix; cell shape irregular to round

Question 7

types of connective tissue

Answer 7

loose
dense
adipose
blood cartilege bone

Question 8

what are the main tissue types in the body

Answer 8

epithelial
connective
muscle
neural

Question 9

muscle tissue function

Answer 9

generate contratile force

minimal matrix, external lamina

makes up skeletal muscles, hollow organs and tubes

cells linked in sheets or elongated bundles; cells shapes in elongated, thin cylinders; heart muscle cells may be branched

Question 10

muscle tissue types

Answer 10

smooth, skeletal and cardiac

Question 11

neural tissue

Answer 11

neurons - info transfer (chemical/electrical)
glial cells - support for neurons, physical and biophysical support

minimal matrix; external lamina

are located throughout body, concentrated in brain and spinal cord

cells isolated or networked; cell appendages highly branched and/or elongated

Question 12

which types of tissues are excitable

Answer 12

neural and muscle

Question 13

apical

Answer 13

faces lumen or external environment

Question 14

basolateral

Answer 14

faces ECM and ECF membranes

Question 15

what is connective tissue made up of

Answer 15

cells and extensive extracellular matrix
proteoglycans and insoluble protein fibers
consistency (liquid, gel, solid) depends on tissue type

Question 16

loose connective tissue

Answer 16

elastic tissues beneath skin and between some cells
very flexible

ie/ fibroclasts

Question 17

dense connective tissue

Answer 17

provides strength and flexibility. collagen fibers of tendons densely packed
e.g. tendons and ligaments

Question 18

excitable cells in muscle and neural tissue

Answer 18

can generate and transmit electrical signals
minimal extracellular matrix

Question 19

what is membrane permeability proportional to

Answer 19

lipid solubility/ size

Question 20

what is highly permeable in a membrane

Answer 20

gases small lipophilic (hydrophilic) molecules, water

Question 21

what is impermeable to cell membrane

Answer 21

ions, lipophobic (hydrophilic, polar) and large molecules

Question 22

diffusion

Answer 22

movement of molecules from an area of higher concentration to lower concentration

passive

no energy input needed

theres both simple and facilitated

Question 23

equation for fick’s law of diffusion

Answer 23

rate of diffusion is proportional to SA x concentration gradient x membrane permeability

Question 24

function of structural proteins

Answer 24

connect to cytoskeleton, ECM, form cell junctions

Question 25

function of enzymes

Answer 25

catalyze reactions, involved in signaling/communication

Question 26

function of membrane transporters

Answer 26

move things across membranes - channels and carrier proteins

Question 27

functions of receptors

Answer 27

cell signaling/communication, vesicular transport

Question 28

facilitated diffusion

Answer 28

passive transport molecules move down their concentration gradients towards equilibrium

Question 29

active transport

Answer 29

requires energy input molecules move against their concentration gradients and move away from equilibrium

Question 30

channels

Answer 30

facilitated diffusion usually only allow one thing through at a time selective

Question 31

carriers (transporters)

Answer 31

flip/flop slow - because of conformation change facilitated diffusion or active transport open to one side of the membrane or the other (inward and outward conformations) may be selective, can carry large molecules than channels

Question 32

passive/leak channels

Answer 32

are always open and conducting ie/ potassium leak channel

Question 33

voltage gated channels

Answer 33

open and close in response to changes in membrane voltage, sodium and potassium

Question 34

ligand gated channels

Answer 34

open when a specific chemical molecule binds to the channel protein ie/ neurotransmitter gated channels

Question 35

mechanically gated channels

Answer 35

open and close in response to physical disturbance/stress of membrane stress/ stretch gated

Question 36

what does channel selectively depend on

Answer 36

diameter of pore electrical charge of amino acids lining the pore

Question 37

uniport carriers

Answer 37

transport only one kind of substrate one molecule, one direction

Question 38

symport carriers

Answer 38

move two or more substrates in the same direction across the membrane two molecules, same directions

Question 39

antiport carriers

Answer 39

move substrates in opposite direction require ATP two substances, opposite directions

Question 40

primary active transport

Answer 40

directly uses ATP as its energy source (ATPases)

Question 41

secondary active transport

Answer 41

uses potential energy stored in concentration gradients from other molecules either symport or antiport

Question 42

ATP

Answer 42

metabolic product of glycolysis, the citric acid cycle and the electron transport system releases energy when phosphate bonds are broken

Question 43

sodium potassium pump

Answer 43

1. sodium high in ECF. 3 sodiums from ICF bind to high affinity sites. Sodium is low on inside. Inward facing conformation 2. ATPase is phosphorylated with Pi from ATP. Protein changes conformation 3. Sodium binding sites lose their affinity for sodium and release 3 sodium into ECF. High affinity binding sites for potassium appear 4. 2 potassium from ECF bind to high-affinity sites. Potassium concentration low on the ECF. 5. Potassium binding sites lose their affinity for potassium and release two potassium into ICF. High affinity sites for sodium appear.

Question 44

Sodium-glucose transporter

Answer 44

secondary active transport 1. sodium binds to carrier. Sodium high in ECF, glucose low. 2. sodium binding creates a high affinity site for glucose. 3. glucose binding changes carrier conformation so that binding sites now face ICF 4. sodium is released into cytosol, where sodium concentration is low. Release changes glucose-binding site to low affinity. Glucose is released.

Question 45

trancellular transport

Answer 45

transport through cells via simple diffusion, facilitated diffusion, active transport, endo/exocytosis ions or molecules cross both apical and basolateral membranes

Question 46

paracellular transport

Answer 46

molecules pass between adjacent cell to get to or from lumen regulated by the presence of tight junctions