Animal Physiology Chapter 24

What is tissue's venous oxygen partial pressure determined by?

1. rate of blood flow through tissue 2. arterial oxygen 3. amount hemoglobin/volume 4. rate of oxygen consumption

a shift in pH to the alkaline side of the animal's normal pH

alkalosis

What is the amount of oxygen carried/volume at saturation?

carrying capacity

respiratory pigment that resembles hemoglobins and occurs in just four families of marine annelid worms; always found extracellularly, dissolved in the blood plasma

chlorocruorins

the venous O2 partial pressure below which aerobic catabolism becomes impaired

critical venous O2 partial pressure

effect that results from influences of the proton (H+) concentration on respiratory-pigment molecules

fixed-acid Bohr effect

metalloporphyrin containing iron in the ferrous state

heme

iron-based respiratory pigments that do not contain heme and occur in three or four very different phyla; can appear in muscle cells

hemerythrins

What is the most widely distributed respiratory pigment?

hemoglobin

consist of heme and globin and are the most widespread respiratory pigments

hemoglobins

Where does all blood hemoglobin reside in verts?

inside RBC (intracellular)

Pigments change color when ___________________ and _______________________.

oxygenated and deoxygenated

occurs when the exhalation of CO2 is impaired and metabolically produced CO2 therefore accumulates excessively in the body

respiratory acidosis

When the respiratory pigment in the blood is ___________, the O2 partial pressure is high enough for all binding sites to be oxygenated.

saturated

How many amino acids does hemoglobin have?

~140

How are respiratory pigments similar to enzymes?

1. defined, highly specific binding sites for oxygen 2. noncovalent, weak bonding that changes pigment's shape 3. affinity 4. other molecules act as allosteric ligands - baind to a different bindng site and affect affinity for O2

How do globins vary?

1. spatially among tissues 2. developmentally

In many ectothermic verts and inverts, adults can have how many forms of hemoglobin?

2, 4, 10+

organophosphate synthesized in red blood cells from intermediates of glycolosis; reduces the O2 affinity of the hemoglobin molecules with which it binds.

2,3-DPG

What is the Bohr effect?

Affinity for O2 decreases as pH decreases or CO2 partial pressure increases.

effect that results from the immediate influences of increased CO2 partial pressures on respiratory-pigment molecules

CO2 Bohr effect

a phenomenon where the carbon dioxide equilibrium curve depends on blood oxygenation; when said effect is present, deoxygenation promotes CO2 uptake by the blood, whereas oxygenation promotes CO2 unloading

Haldane effect

mathematical index that expresses the extent of cooperativity, which varies from one respiratory pigment to another

Hill coefficient

the partial pressure of O2 at which a pigment is 50% saturated

P50

the reduction in the amount of O2 bound to the pigment at saturation

Root effect

the pattern of absorption by a pigment when expressed as a function of wavelength

absorption spectrum

occurs when the pH of the body fluids is shifted to the acid side of an animal's normal pH at a given body temperature

acidosis

the property of respiratory pigments of various animals to vary widely in how readily they combine with O2

affinity for O2

All hemes are ________, globins _________ in ____________ and ________________.

alike; differ, structure, number

the hypothesis that the changes in pH are a means of maintaining a constant state of electrical charge on protein molecules

alphastat hypothesis

"Hemo" means...

blood

the percentage of arterial O2 that is released to the systemic tissues

blood oxygen utilization coefficient

What are other things that respiratory pigments do?

buffer blood, carbon dioxide transport, intracellularly to facilitate diffusion and store oxygen, synthesize and breakdown nitric oxide (NO)

a plot of the total carbon dioxide concentration as a function of CO2 partial pressure

carbon dioxide equilibrium curve

an enzyme that greatly accelerates the interconversion of CO2 and HCO3-, thereby preventing this reaction from acting as a bottleneck

carbonic anhydrase (CA)

When hemoglobin is not combined with O2

deoxyhemoglobin

How are respiratory pigments unlike enzymes?

don't alter oxygen, just bind and release it

two types of Bohr effects

fixed-acid Bohr effect and a CO2 Bohr effect

What is protein known as (in terms of blood vocab)?

globin

copper-based respiratory pigment that is found in only two phyla, the arthropods and the molluscs; second most common class of respiratory pigment; never found in muscle or other solid tissue

hemocyanins

the four chemical categories of respiratory pigments

hemoglobins, hemocyanins, hemerythrins, chlorocruorins

Blood arrives at capillaries with _______ partial pressure of oxygen.

high

Pigments that load fully at low partial pressures and consequently also require low partial pressures for substantial unloading are said to have a ________ __________ for O2.

high affinity

Pigments that require relatively high O2 partial pressures for full loading and that conversely unload substantial amounts of O2 at relatively high partial pressures are said to have a __________ _________ for O2.

low affinity

__________ disturbances of pH initially alter the blood bicarbonate concentration

metabolic

proteins that contain metal atoms, like the iron in hemoglobin

metalloproteins

blood drawn from the great veins leading back to the heart

mixed venous blood

What structure do myoglobins have?

monomeric, distinct globin structure

Hemoglobins are usually ____________________ proteins.

multisubunit

muscle hemoglobin; single-unit molecules

myoglobin

a phenomenon where myoglobin increases the rate of O2 diffusion through the cytoplasm of the cells

myoglobin-facilitated O2 diffusion

What are intracellular muscle hemoglobins?

myoglobins

In hemoglobin, how much oxygen can you bind per heme?

one

Respiratory pigments increase what?

oxygen carrying capacity

this shows the functional relation between the percentage of binding sites that are oxygenated and the O2 partial pressure

oxygen equilibrium (dissociation) curve

What is another term for respiratory pigments?

oxygen transport pigments

the total amount of O2 that can be carried by each unit of volume of blood

oxygen-carrying capacity

When hemoglobin is combined with O2

oxyhemoglobin

the percentage of binding sites that are oxygenated

percent saturation

the aqueous solution of the blood in which the cells are suspended; obtained by removing all cells from the blood

plasma

specialized cells that contain the blood hemoglobins of vertebrates; vary in sized, shape, and other properties

red blood cells (erythrocytes)

The _________ disturbances of pH are ones that are brought about by an abnormal rate of CO2 elimination by the lungs or gills.

respiratory

occurs when the exhalation of CO2 is abnormally increased relative to CO2 production, causing the CO2 partial pressure in the body fluids to be driven below the level needed to maintain a normal pH

respiratory alkalosis

they are different types of metalloproteins that undergo reversible combination with molecular oxygen (O2); they are also strongly colored

respiratory pigments/ oxygen-transport pigments

all tissues other than the tissues of the breathing organs

systemic tissues

Most hemoglobins of verts are... (hint: 4 subunits)

tetrameric

the total amount of CO2 that must enter each unit of blood volume to raise the blood CO2 partial pressure from zero to any particular positive CO2 partial pressure

total carbon dioxide concentration

the remaining amount of O2 in mixed venous blood during exercise

venous reserve

Is extracellular hemoglobin smaller or larger than intracellular?

very large

the volume of gas carried per 100 volumes or blood

volumes percent (vol %)

Where are hemoglobins found in inverts?

wide and sporadic distribution; tissue, blood, other fluid; extra or intracellular