Lecture 2

Question 1

what are the 4 major tissue types of the body

Answer 1

• epithelial
• connective tissue cells
• muscle
• neural

Question 2

describe epithelial tissue

Answer 2

function - protect internal environment of the body and regulate exchange of materials between internal/external environment
cell types - exchange, protective, ciliated, transporting, secretory

Question 3

describe connective tissue

Answer 3

function - provides structural support and physical barriers
- found within extensive extracellular matrix network
cell types - blood cells, bone cells, fibroblasts

Question 4

describe muscle tissue

Answer 4

function - generate contractile force
cell type - smooth, skeletal, cardiac

Question 5

describe neural tissue

Answer 5

neurons - info transfer (chemical/electrical)
glial cells- support for neurons

Question 6

what are the 5 types of epithelial tissue

Answer 6

• exchange
• ciliated
• transporting
• secretory
• protective

Question 7

what are the 4 functional categories of exchange epithelium

Answer 7

number of layers -1
cell shape - flattened
features - pores between cells permit easy passage of molecules
location - lungs, lining of blood vessels

Question 8

what are the 4 functional categories of transporting epithelium

Answer 8

number of layers - 1
cell shape - columnar or cuboidal
features - tight junctions prevent movement between cells, microvilli which increase surface area
location - intestine, kidney, some exocrine glands
function - selective secrertion/absorption of ions and nutrients

Question 9

what are the 4 functional categories of ciliated epithelium

Answer 9

number of layers - 1
cell shape - columnar or cuboidal
features - one side covered with cilia to move fluid across surface
location - nose, trachea, upper airways, female reproductive tract

Question 10

what are the 4 functional categories of protective epithelium

Answer 10

number of layers - many
cell shape - flattened in surface layers, polygonal in deeper layers
features - cells tightly connected by many desmosomes
location - skin and lining of cavities that open to the environment
function - prevent exchange, protect from mechanical and chemical stress

Question 11

what are the 4 functional categories of secretory epithelium

Answer 11

number of layers - one to many
cell shape - columnar or polygonal
features - protein secreting cells filled with membrane bound secretory granules and extensive RER
- steroid secreting cells contain lipid droplets and extensive SER
location - exocrine glands: pancreas, sweat glands, and salivary glands, endocrine glands: thyroid and gonads
function - secrete hormons, sweat, enzymes, mucus

Question 12

what is connective tissue made up of

Answer 12

• cells and extensive extracellular matrix
• proteoglycans and insoluble protein fibers
• consistency depends on tissue type

Question 13

what are the 6 types of connective tissue

Answer 13

• loose connective tissue
• dense connective tissue (regular and irregular)
• adipose tissue
• blood
• cartilage
• bone

Question 14

describe loose connective tissue

Answer 14

• very flexible with multiple cell types and fibers
• contain fibroblasts -> cells that secrete matrix proteins
• ground substance is the matrix of loose connective tissue
• lots of collagen fibers

Question 15

describe bone and cartilage connective tissue

Answer 15

• hard bone forms when osteoblasts deposit calcium phosphate crystals in the matrix
• cartilage has firm but flexible matrix secreted by cells called chondrocytes

Question 16

describe blood

Answer 16

• consists of liquid matrix (plasma) plus red and white blood cells and the cell fragments called platelets

Question 17

describe adipose tissue

Answer 17

• in white fat the cell cytoplasm is almost entirely filled with lipid droplets
• brown fat and white fat

Question 18

describe dense regular connective tissue

Answer 18

• collagen fibers of tendon are densely packed into parallel bundles
• tendons and ligaments
• fibroblasts

Question 19

describe dense irregular connective tissue

Answer 19

• mostly collagen, random
• fibroblasts
• muscle and nerve sheaths

Question 20

describe muscle and neural tissue

Answer 20

• excitable cells
• able to generate and transmit electrical signals
• minimal extracellular matrix

Question 21

what is membrane transport

Answer 21

• substances in the body must move across cell membranes which act as physical barriers
• cell membranes are selectively permeable
• hydrophobic phospholipid bilayer
• transport depends on lipid/protein composition

Question 22

how does cholesterol affect the membrane permeability

Answer 22

• increase in membrane cholesterol = decrease in water permeability

Question 23

what determines the membrane permeability of a molecule

Answer 23

• its physical properties influence its ability to move directly across a membrane
• membrane permeability -> lipid solubility/molecular size

Question 24

what is highly permeable

Answer 24

• gases, small lipophilic (hydrophobic) molecules, water

Question 25

what are the impermeable ions

Answer 25

- ions, lipophobic (hydrophilic, polar) and large molecules

Question 26

what are the different membrane transport mechanisms

Answer 26

- non facilitated transport - simple diffuison - facilitated transport - protein mediated transport -> channels vs transporters -> passive: facilitated diffusion -> active: primary or secondary active transport - vesicular transport -> endocytosis and exocytosis -> phagocytosis

Question 27

what is diffusion

Answer 27

- movement of molecules from an area of higher to lower concentration - down a chemical/concentration gradient - passive process = no energy input required

Question 28

what are the factors affecting rate of diffusion through a cell membrane

Answer 28

- lipid solubility - molecular size - concentration gradient - membrane surface area - composition of lipid layer

Question 29

what is ficks law of diffusion

Answer 29

rate of diffusion = surface area x concentration gradient x membrane permeability

Question 30

what is protein mediated membrane transport and the 2 types

Answer 30

- required for larger or lipophobic atoms or molecules - facilitated diffusion (passive transport) - molecules move down their concentration gradient towards equilibrium - active transport (requires energy) - molecules move against their concentration gradients and system moves away from equilibrium

Question 31

what are the 2 types of transport proteins

Answer 31

channels - water filled pores linking EC and IC environment - facilitated diffusion (passive transport) - selective about the substances they allow to pass - small molecules - water channels - ions channels - some have gates to regulate flow - transport is fast carriers - transporters - open to on side of the membrane or the other - facilitated diffusion or active transport - may be selective, can carry large molecules - transport is much slower

Question 32

what are the 4 types of membrane channels

Answer 32

1. passive/leak channels - always open and conduction 2. voltage gated channels - open and close in response to changes in membrane voltage 3. ligand gated channels - open when specific chemical molecules bind to the channel protein 4. mechanically gated channels - open and close in response to physical disturbance of membrane

Question 33

what is channel selectivity and what does it depend on

Answer 33

- a membrane channel is selective with what it allows to pass through its pore - selectivity depends -> diameter of the pore -> electrical charge of amino acids lining the pore

Question 34

what are the 3 types of carrier proteins

Answer 34

uniport - transport only one kind of substrate symport - move 2 or more substrates in the same direction antiport - move substrates in the opposite directions

Question 35

describe active transport and the 2 types

Answer 35

- molecules move against their concentration gradient and system moves away from equilibrium - primary active transport -> directly uses ATP as its energy source - secondary active transport -> uses potential energy stored in concentration gradients from other molecules -> either via symport or antiport mechanisms

Question 36

what is ATP

Answer 36

- adenosine triphosphate 1. metabolic product of glycolysis, the citric acid cycle, and the electron transport chain 2. releases energy when the phosphate bonds are broken (ATP -> ADP + Pi -> AMP + Pi)

Question 37

explain an example of primary active transport

Answer 37

Na+ K+ ATPase -> critical from homeostasis and cell function 1. 3 Na+ from ICF bind to high affinity sites 2. ATPase is phosphorylated with Pi from ATP (change in conformation) 3. Na binding sites lose their affinity from Na+ and release 3 Na+ into ECF (high affinity binding sites for K+ appear) 4. 2 K+ from ECF bind to high affinity sites 5. high affinity binding sites for Na+ appear

Question 38

explain an example of secondary active transport

Answer 38

sodium glucose transporter 1. Na+ binds to carrier 2. Na+ binding creates a high affinity site for glucose 3. glucose binding changers carrier conformation so that binding sites now face the ICF 4. Na+ is released into cytosol where [Na] is low -> release changes glucose binding site to low affinity -> glucose is released

Question 39

explain how larger molecules or complexes move across membranes

Answer 39

endocytosis/exocytosis 1. ligand binds to membrane receptor 2. receptor-ligand migrates to clathrin coated pit 3. endocytosis 4. vesicle loses clathrin coat 5. receptor and ligands separate 6. ligands go to lysosome or golgi for processing 7. transport vesicle with receptors moves to the cell membrane 8. transport vesicle and cell membrane fuse 9. exocytosis

Question 40

compare epithelial cell transport transcellular transport vs paracellular transport

Answer 40

transcellular transport - transport through cells via simple diffusion, facilitated diffusion, active transport, endo/exocytosis - ions or molecules cross both apical and basolateral membranes paracellular transport - molecules pass between adjacent cells to get to or from lumen - regulated by presence of tight junctions