Chapter 7.3 Flashcards
What is high blood pressure?
- it is referred to as hypertension
- >damages blood vessels and organs
What is blood pressure in terms of force and area
- it is the measure of force per unit of area on the wall of blood vessels
- > measured with a sphygmomanometer
Where is the largest drop in pressure in terms of the blood vessels
-it is across the arterioles
Describe resistance in relation to that of blood vessels
- the longer a blood vessel is, the more resistance it offers
- the larger the cross sectional area, the less resistance the blood vessels offer
-arteries are highly muscular and are able to expand and contract as needed to change vascular resistance and maintain blood pressure
How is blood pressure regulated
- it is regulated using baroreceptors in the walls of the vasculature
- > baroreceptors detect changes in mechanical forces on the walls of the vessels
- > when blood pressure is low, the baroreceptors stimulate the sympathetic nervous system
- > this stimulation causes vasoconstriction, increasing blood pressure
What does high osmolarity mean? What does it result in?
- high osmolarity= dehydration
- > it motivates the body to release ADH
- > ADH is a peptide hormone made in the hypothalamus but stored in the posterior pituitary
-the osmolarity of the blood being high can be detected by the chemoreceptors
What if blood pressure becomes too high?
- then atrial cells within the heart release ANP
- > ANP is atrial natriuretic peptide
- ANP aids in the loss of salt within the nephron
- > water follows
What does oxygen saturation refer to?
- it refers to the percentage of hemoglobin molecules carrying oxygen
- > it is measured using a finger probe
What type of binding is it when oxygen molecules bind to hemoglobin, which induces further binding of other oxygen molecules to hemoglobin?
-this is referred to as cooperative binding
- the binding of oxygen occurs at the heme group’s central iron aton
- > the central iron atom undergoes changes in oxidation state
- > the binding or release of oxygen to or from the iron atom in the heme group is an oxidation-reduction reaction
What does the vast majority of CO2 exist in the blood as
- it exists as the bicarbonate ion(HCO3-)
- CO2 is first converted to carbonic acid thanks to carbonic anhydrase
- > then it is converted to a hydrogen ion and a bicarbonate ion afterwards
What is the Bohr effect?
- increased carbon dioxide concentration= increased hydrogen ions and decreased pH
- > these protons can bind to hemoglobin, reducing hemoglobin’s affinity for oxygen
- > decreased affinity= shift in the oxyhemoglobin curve to the right
-note decreased affinity for oxygen allows for more offloading of oxygen in the tissues
What happens to Co2 concentrations in the blood during hyperventilation
- it decreases
- > shifts the bicarbonate buffer system to the left and decreases the concentration of protons, leading to an increased pH
- > eventually leads to respiratory alkalosis
What is hydrostatic pressure?
- it is the force per unit area that the blood exerts against the vessel walls
- > it is generated by the contraction of the heart and the elasticity of the arteries
-its pressure pushes fluid out of the bloodstream and into the interstitium through capillary walls
What is osmotic pressure
- it is the sucking pressure generated by solutes
- > as they attempt to draw water into the BLOODSTREAM
- > note osmotic pressure is also referred to as oncotic pressure because of the fact that it is due to plasma proteins
Describe the hydrostatic pressure and oncotic pressure in relation to the arteriole end and the venule end
Arteriole end
- > hydrostatic pressure is much larger than the oncotic pressure
- > so there is a net efflux of water from the circulation
Venule end
- > hydrostatic pressure is less than the oncotic pressure
- > so there is a net efflux of water into the circulation
