Homeostasis,body Fluids,and Transport Mech

Question 1

What is homeostasis following that what is ECF?

Answer 1

The body maintains a relatively stable internal conditions even though the external environment changes continuously.
A constant internal milieu is required for good health

Question 2

Homeostatically regulated variables

Answer 2

Homeostatic mechanisms operate continuously maintain all the time It has to have a sensor that initiate a response the variable are maintain to homeostatic.Blood glucose levels increase after eating, the levels change over short periods of time but remain constant over long period of time.

Question 3

regulated(sensed) variable is _ and the non regulated (controlled) variable is_

Answer 3

1. blood pressure because a sensor exist for this variable
2. heart rate there is no sensor for these variables

Question 4

The_ is the normal range for regulated vairable while the _ detects value of regulated variable and transduce stimulus into a physiological signal

Answer 4

1. Setpoint
2. Sensor

Question 5

They are part of the control center in homeostatic . This one_ compare value of new frequency and the second one interprets error signal and determines the output of effectors_

Answer 5

1. Error detector
2. Integrator exemple of this one is the neuron, circuit or brain region

Question 6

It change value of regulated variable like in muscle tone exemple of this one is cells, tissues, smooth muscles and glands

Answer 6

Effectors

Question 7

change that turn variable to the set point

Answer 7

Effectors from homeostatic regulatory system

Question 8

homeostatic imbalance

Answer 8

1. Depend on external resources
2. Sensors respond within a limited range of stimulus values

Question 9

Homeostatic imbalance exemple

Answer 9

certain disease or illnesses characterized as a loss of homeostasis in one or more systems. Dramatic changes in just one variable can have life threatening consequences. When homeostasis is lost for one varaible, it may trigger a series of changes in other variables leading to a cascade of problem . One exemple if an individual keeps running he might pass out eventualy.

Question 10

Negative feedback

Answer 10

returns variable to set point

Question 11

Positive feedback

Answer 11

pushes variable away from set point

Question 12

feed-forward control

Answer 12

anticipatory;minimizes changes to variables

Question 13

Fluid in the blood (plasma) there is 7 % of water in this compartiment

Answer 13

extracellular fluid (ECF)

Question 14

Between cells and contain 26 % of water

Answer 14

Interstitial fluid (ISF)

Question 15

It contains 67% of water

Answer 15

Intracellular fluid (ICF)

Question 16

transport of substances across the Peripheral membrane

Answer 16

1. Passive transport: no energy input is required
2. Active transport: energy ATP is required to move substance against their concentration gradient (uphill)

Question 17

It is going downhill and involves diffusion-movement of molecules from high to low; referred to as moving down a concentration gradient; differnet kind exist: simple diffusion, facilitated diffusion and osmosis

Answer 17

Passive transport

Question 18

how does diffusion works?

Answer 18

all molecules have random , high speed movement due to their intrinsic kinetic energy. The movement results in collision between molecules. When the dye is evenly distributed there is no more net movement because there is no more concentration gradient

Question 19

Factors that affect diffusion rate

Answer 19

1. Molecular size
2. Temperature
3. Concentration
4. Surface area
5. Medium (viscosity)

Question 20

It is reached when there is no net movement of molecules in either direction. This one happens naturally and doesnt require energy

Answer 20

Equilibrium

Question 21

Simple diffusion through memebranes

Answer 21

Non polar, lipid-soluble (hydrophobic) substance diffuse directly through phospholipid bilayer.
oxygen, carbon dioxide, steroid hormones, fatty acids and small amounts of very small polar substance like water can pass

Question 22

Facilitated diffusion

Answer 22

Larger, non-lipid soluble, or polar molecules can cross membrane but only with assistance of carrier molecules
1. Carrier-mediated
2. Channel-mediated
use different types of integral membrane proteins
it imprat differnt properties to the transport process

Question 23

Carrier-mediated facilitated diffusion

Answer 23

certain hydrophilic molecules (glucose, amino acids and ions) are transported passively down their concentration gradient by carriers (transmembrane proteins)

• each of the carrier transports specific substance
• binding of molecule causes carrier to change shape and results in molecule being moved across membrane

Question 24

Channel-mediated facilitated diffusion

Answer 24

some integral membrane protein form channels that allows ions to diffuse across the membrane
- ion channels show selectivity for a particular type of ion (Na and K) based on chanel diameter, charged residues lining pore, water of hydration

Question 25

regulation of diffusion through ion channels

Answer 25

ion channel-open or closed state. Opening and closing channels is known as gating - for a given electrochemical gradient the number of ions that are conducted by the channel depends on : 1. how often the channel opens 2. How long it stays open gated channels: 1. Ligand-gated; 2. Voltage-gated; 3. Mechanically-gated a given ion may pass through several types of channels

Question 26

Three factors determine the magnitude of solute flux through a mediated transport system

Answer 26

1. The extent to which the binding sites are saturated 2. The number of transporters in the membrane 3. The rate at which the conformational change occurs

Question 27

there are two type of carrier mediated transport

Answer 27

4. Facilitated diffusion 5. Active transport

Question 28

Primary active transport

Answer 28

the hydrolysis of ATP provides the energy for primary active transport Transporters are ATPases-enzymes that hydrolyze (breaks down using water ) ATP. Na+/K+ ATPase pump

Question 29

Na+/K+ ATPase pump

Answer 29

1. The transporter(with bound ATP) binds 3 Na+ on inside of cell (low affinity for K+) 2. ATPase activated. Auto-phosphorylation 3. Conformational change and release of Na+ to outside 4. Increased affinity for K+ allows two K+ to binds 5. Dephosphorylation and return to original conformation. Release of K+ to inside.

Question 30

Na+/K+ ATPase establishes electrochemical gradient

Answer 30

The pumping activity of the Na+/K+ ATPase establishes and maintains the characteristic distribution of high K+i and low Na+ inside and high Na+ and low K+ outside The Na+/K+ ATPase estacblishe chemical gradient that can be used to do work Between 10 to 40 % of the ATP a cell produces under resting condition is used by the Na+/K+ ATPase pump to maintain the sodium gradient

Question 31

Role of electrical force in ION movements

Answer 31

The unequal distribution of ions induces a seperation of electrical charges across the plasma membrane - called the membrane potential (electrical force) The direction and magnitude of ion fluxes across membrane depend on both the concentration and the mmebrane potential. The two driven forces are known as electrochemical gradient

Question 32

secondary active transport

Answer 32

the energy stored in an electrochemical gradient can be used to drive the transport of other solutes. The movment of an ion down its electrochemical gradient is coupled to the transport of another molecule (ex. glucose, amino acids) These transporters have binding sites for ion (usually Na+) and the cotransported molecule. It uses the stored energy of an electrochemical gradient to move both an ion and a second solute across a membrane

Question 33

cotransport (symport)

Answer 33

The ion and the second solute cross the membrane in the same direction the movement of Na+ is always downhill, from high to low

Question 34

countertransport (antiport)

Answer 34

the ion and the second solute move in opposite directions downhill from high to low

Question 35

osmosis

Answer 35

water diffuses across plasma membrane - some through lipid balayer - mostly through specific water channels called aquaporines The flow occurs when the water concentration is different on the two sides of a membrane = movement of solvent across a selectively permeable membrane

Question 36

a semi permeable membrane is called_

Answer 36

osmosis

Question 37

osmolarity

Answer 37

total number of solute particles in a solution 1M glucose is 1 osmol/L 1M NaCl ionizes to Na+ and Cl- (2 particles) is 2 Osm (osmolar) 1M solution of MgCl2 is 3 Osm A 3 Osm solution may have 1 M glucose and 1 M NaCl - ICF and ECF is 300 mOsm

Question 38

membrane permeable to both solutes and water

Answer 38

both solute and water molecules move down their concentrstion gradients

Question 39

memebrane permeable to water, impermeable to solutes

Answer 39

water moves by osmosis from an area of higher to lower water concentration (lower to higher solute concentration )

Question 40

hydrostatic pressure

Answer 40

outward pressure exerted on cell side of membrane caused by increases in volume of cell due to osmosis

Question 41

osmotic pressure

Answer 41

inward pressure due to tendency of water to be pulled into a cell with higher osmolarities the more solutes inside the cell, the bigger the pull on water to enter, resulting in higher osmotic pressures inside the cell

Question 42

when hydrostatic pressure equals osmotic pressure there is_

Answer 42

no further net movement of water occurs where the water trying to get out= water trying to get in

Question 43

Refers to the concentration of ALL solutes, peetrting (p) and non-penetrating (np)

Answer 43

Hyper-osmotic, iso-osmotic and hypo-osmotic

Question 44

refer to the concentration of non-penetrating solutes

Answer 44

Hypertonic, isotonic and hypotonic Na+, Cl- and K+

Question 45

hypotonic solutions

Answer 45

cells take on water by osmosis until the become bloated and burst (lyse) It contains a lower concentration of non penetrating solutes than are present inside cells

Question 46

hypertonic solutions

Answer 46

cells lose water by osmosis and shrink contains a higher concentration of nonpenetrating solutes than are present inside the cells

Question 47

Isotonic solutions

Answer 47

Cells retain their normal size and shape same solute/water concentration as inside cells; water moves in and out