Chapter 19 - The Cardiovascular System - Blood Vessels
State of abnormally high hydrogen ion concentration in the extracellular fluid.
Hormone produced by the adrenal cortex that regulates Na+ reabsorption. Water there for followings, and blood volume increases ---> increase in Blood pressure
A vasoconstrictor activated by renin
Promotes release of Aldosterone and ADH (Antidiuretic Hormone)
Promotes vasoconstriction and water conservation by the kidneys, resulting in increase of blood volume.
Atrial natriuretic peptide (ANP)
Acts as a vasodilator and an antagonist to aldosterone, resulting in drop in blood volume
Blood pressure (BP)
Force exerted by blood against a unit area of the blood vessel walls; differences in blood pressure between different areas of the circulation provide the driving force for blood circulation.
Cardiac output (CO)
Amount of blood pumped out of a ventricle in one minute.
Colloid osmotic pressure
Pressure created in a fluid by large non-diffusible molecules, such as plasma proteins that are prevented from moving through a (capillary) membrane. Such sub- stances tend to draw water to them
Arterial blood pressure reached during or as a result of diastole; lowest level of any given cardiac cycle.
How much the elastic arteries close to the heart stretch
A state of constant moderate constriction of the arterioles
Is the force exerted by a fluid pressing against a wall.
Hepatic portal system
Circulation in which the hepatic portal vein carries dissolved nutrients to the liver tissues for processing.
Immunity conferred by antibodies present in blood plasma and other body fluids.
Receptor sensitive to mechanical pressure such as touch, sound, or exerted by muscle contraction
A measure of the tendency of water to move into a more concentrated solution.
Receptor located in a joint, muscle, or tendon; concerned with locomotion, posture, and muscle tone.
Enzyme released by the kidneys that raises blood pressure by initiating the renin-angiotensin-aldosterone mechanism.
System of blood vessels that serves gas exchange in the body tissues.
Brain area concerned with regulation of blood vessel resistance.
Mean arterial pressure (MAP)
the pressure that propels the blood to the tissues.
Elastic Arteries - (Conducting)
Thick-walled arteries (pulmonary & descending aorta)
With large lumen and found near heart
Largest diameter with most elastin
They expand and recoil to accommodate changed in blood volume which results in the blood being kept under pressure
Muscular Arteries - (Distributing)
Thickest tunica media of all BV
They deliver blood to specific organs
More active in vasoconstriction (due to more smooth muscle in t. media)
Smallest of arteries
Regulate blood flow to the capillary beds
Most are single layer smooth muscle around the endothelial lining
Only thin tunica media
Large enough for single file RBC to pass by
Found in skin and muscle
They are endothelial cells that provide an uninterrupted lining
Similar to continuous
Have pores so nutrients can diffuse
Found in small intestines and kidneys (where absorption occurs)
Irregular shaped lumens that allow passage of large molecules (proteins & blood cells)
Found in liver, blood, and marrow
Interweaved networks that are regulated by vasomotor nerve fibers & local chemical conditions
They can be flooded or shunted if blood is needed in other parts of body
Venous vessels increase in diameter & their walls thicken at you get closer to the heart
Smallest - Postcapillary venule
Extremely porous so fluid and WBC from blood stream can move easily through walls
Sparse tunica media and externa
Wall thinner and lumen is larger than corresponding arteries
Called blood reservoir
Have semi-lunar valves; most abundant in veins in limbs
Are flattened veins with thin walls and supported by tissues around them
The actual volume of blood flowing through and area in a given period
Area of flow could be a vessel, an organ, or the entire circulation
Force that blood exerts on a given area of a blood vessel wall
If term is used with not specification to location of body, it is the systemic arterial blood pressure in the larges arteries near the heart
Pressure gradient keeps blood moving
Opposition to blood flow. It is the measure of the amount of friction blood encounters as it passes through the blood vessels
Peripheral resistance - most resistance
Three sources: BV length, BV diameter, viscosity of blood,
Factor of resistance - Viscosity of blood
Is resistance to flow caused by molecular interactions within a fluid (different parts of river flowing)
Under normal conditions, blood viscosity is fairly constant
Dehydration or polycythemia will increase blood viscosity
Anemia will reduce viscosity
Factor of resistance - BV length
Longer the BV = more resistance
Factor of resistance - BV diameter
Arterioles have the smallest diameter and change diameter due to neural and chemical controls
Arterioles are major determinants of PR
Influencing factors of Arterial blood pressure:
1) How much the elastic arteries close to the heart stretch? (compliance)
2) The volume of blood forced into the arteries at a particular time
The difference between the systolic and diastolic pressures
The actual "working" pressure of the heart.
It is the amount of force given off by the heart during each cardiac cycle
Why is low capillary blood pressure desirable?
1) capillaries are fragile and high pressures would rupture them
2) most capillaries are extremely permeable and thus even the low capillary pressure can force solute-containing fluids (filtrate) out of the bloodstream into the interstitial space. These fluid flows are important for continuously refreshing the interstitial fluid.
Two systems that help venous return
1) Muscular pump
2) Respiratory pump
Muscular pump - Venous Return
Skeletal muscles surround deep veins. As they contract and relax, blood is "milked" through the veins, successive passing of valves each time.
Respiratory pump - Venous Return
Pressure changes during breathing help suck blood upwards
Inhale - lungs inflate, pressure increases in abdominal cavity, blood moves towards heart - climbing the valve stairs
Exhale - Thoracic cavity decreases, building pressure to push blood towards to heart
Short-term Mechanisms to control Blood pressure
1) Vasomotor Center
2) Baroreceptor-initiated reflexes
3) Chemoreceptor-initiated reflexes
4. Higher Brain Centers
Purpose of short-term mechanisms to control BP?
1) Regulate blood vessel diameter, heart rate, and contractility
2) Regulated by neural and local chemical conditions
Formula for BP
Blood pressure = cardiac output X peripheral resistance
What cells in the kidneys monitor alterations in blood pressure?
What is the role of the Hypothalumus in regulating Blood Pressure?
1.It excites the thirst center stimulating the individual to drink more water, rehydrating blood → restoring blood volume--> increasing blood pressure
What is Peyer's Patch?
1) Aggregates of lymphoid nodules located in the wall of the ileum are
2) Destroy bacteria in appendix; generate "memory" lymphocytes for long-term memory in intestine
Where does extra tissue fluid in Brain drain into?
Cerebrospinal Fluid -(CSF)
Which of the following cells would not be found in a germinal center in a lymph node?
Lymph Node Location:
B-cell Within germinal center
T-cell Deep cortex
Dendritic cells Surrounding the germinal centers
Plasma cells Medullary cords
Macrophages Lymph Sinus