(inner layer, in contact with lumen of the blood vessel) - consists of endothelium, basement membrane, internal elastic lamina
Tunica media
(middle layer) - consists of smooth muscle and external elastic lamina (contraction to monitor the blood flow, blood pressure monitoring, vasospams).
Tunica externa
(outer layer) - elastic and collagen fibers with numerous nerves
Vasoconstriction:
the decrease in the diameter of the lumen of the blood vessel to due increased stimulation of the sympathetic ANS,
Vasodilation:
the increase in the diameter of the lumen of the blood vessel to due the decreased stimulation of the sympathetic ANS
Function of anastomoses:
to provide blood supply to a body part in the event of one part of the artery being blocked by disease,injury ,surgery
Structure and function of Elastic Arteries
Structure: Has more elastic fibers and less smooth muscle in their tunica media.
Function: help propel blood onward while the ventricles are relaxing Muscular arteries adjust the rate of blood flow and distribute blood to organs
Structure and function of Muscular arteries
Structure: contains more smooth muscle and fewer elastic fibers Arterioles: consists of one to two layers of smooth muscle cells having a circular orientation in the vessel wall.
Function: adjust the rate of blood flow and distribute blood to organs
Structure and function of Arterioles
Struture: consists of one to two layers of smooth muscle cells having a circular orientation in the vessel wall.
Function: regulate the flow of blood into capillaries. Also major regulators of blood pressure.
Collateral circulation:
thealternative circulatory route of blood flow to a body part through an anastomosis if a vessel is blocked by disease or injury.
Precapillary sphincters:
Are the most distal muscle cell at the junction of the metarteriole-capillary junction (metarteriole = distal end of an arteriole). It receives input from sympathetic innervation and local chemicals to adjust arteriole diameter, regulating blood flow through capillaries
Function and structure of Capillaries:
Function: exchange of materials between the blood and interstitial fluid, Structure: Single Endothelium layer and Basement membrane
Autoregulation of capillary blood flow is:
The ability of the capillary tissue to regulate its own blood flow according to the metabolic demands at any given time
The function and mechanism of capillary exchange:
Function: it help substance move between blood and interstitial fluid, Mechanism is by diffusion and transcytosis.
Influences on capillary exchange:
Capillary blood pressure “pushes”s fluids out of capillaries into interstitial fluid (filtration).
Stating the function and structure of venules:
Function: Drain capillaries and start the venous return to heart and also are exchange sites for nutrients and wastes and WBC in infected and inflamed tissues. Structure: Thin walled and loosely arranged endothelial cells.
Structure and Function of veins:
Structure: Veins composed tunica interna and turnica externa. They are very thin walls relative to their total diameter.
Function: Veins are blood vessels that take blood from the body tissues back to the heart.
purpose of venous valves:
It helps to prevent the backflow of blood.
Skeletal muscle pump:
1.a muscle is relaxed, both proximal and distal valves are open
2.Muscle contracts, blood pressure increases in the vessel segment between the valve, blood flows out of the proximal open valve
3.Remaining blood in the vessel segment flows back and forces the distal valve shut
4.As the blood pressure in the segment decreases, there is a backflow of blood from above the proximal valve, closing it shut
5.At the same time, the blood pressure increases in the foot, forcing the distal valve open and the cycle repeats
3.Blood flows from the area of higher pressure to the area of low pressure
4.During exhalation, the reverse of events takes place and the valves prevent the backflow of blood from the thoracic to the abdominal cavity.
Varicose veins:
A defect in the valves of the vein that causes leaking or
backflow of blood into more superficial veins leading to pooling of blood(appears dilated and twisted).
Hemorrhoids:
the varices in the veins of the anal canal.
Describe the distribution of blood in the body:
Systemic veins and venules(blood reservoirs) > Systemic arteries and arterioles > Pulmonary blood vessels > Systemic capillaries = Heart chambers.
Define blood flow.
The amount or volume of blood flowing through any tissue at any given time (unit ---mL/min).
Name two factors that influence blood flow.
Pressure difference
Vascular resistance.
Define systolic and diastolic blood pressure.
Systolic blood pressure is the highest pressure during systole.
diastolic blood pressure is the lowest pressure during diastole.
Describe blood pressure in various vessels of the cardiovascular system:
Blood pressure drops progressively as it moves from the aorta (70 mm Hg-110 mm Hg), further away from the left ventricle and back to the right atrium, at 0mm Hg Bloodpath / pressure: In the aorta, leaving arteries [bp dips down, with fluctuations] arterioles, [35 mm Hg] capillaries [bp fluctuations disappear, 16 mm Hg] Venules > Veins > Vena cavae, [0 mm Hg]
Three factors that affect vascular resistance:
thickness of blood (the thicker, the higher the resistance)
length of blood vessel (longer the blood vessel, higher the resistance)
vasoconstriction (increases resistance)
Explain how the cardiovascular center and baroreceptors regulate blood pressure. For Low blood pressure:
Baroreceptors stretched less > a decrease of parasympathetic stimulation by cardiovascular center (by vagus nerve) and increase of sympathetic stimulation of the heart by the cardiac accelerator nerves + secretion of epinephrine and norepinephrine by adrenal medulla > increased stroke volume and heart rate (=increased cardiac output) Cardiovascular center > stimulation of vasomotor nerves of the blood vessels > vasoconstriction and increased systemic vascular resistance > increased blood pressure Regulation: Negative feedback inhibition
Explain how the cardiovascular center and baroreceptors regulate blood pressure. For High blood pressure:
When blood pressure is high,the ascending aorta and aortic arch are streched more. The baroreceptors send impulses faster, sensory nerve impulses increase therefore parasystemathic impulses increase while sympathetic impulses decrease and blood pressure goes back to normal. The increase in parasympathetic tone to sympathetic tone results in lower blood pressure via decreasing heart rate, decreasing the force of heart contractions, and causing vasodilation of blood vessels.
Baroreceptors are:
blood pressure receptors located in the aorta, internal carotid artery and other arteries in the neck and chest.
Define pulse:
the alternate expansion and elastic recoil of an artery after every rythmic contraction and relaxation of the left ventricle.
Where on the body can the Pulse be felt:
The Pulse can be felt in any artery that lies near the body surface.
Tachycardia is
An abnormally high heart rate (100 beats/min & above).
Bradycardia is:
An abnormally low heart rate (below 60 beats/minute).
Define hypotension:
Hypotension can be define as abnormally low blood pressure. When the systolic blood pressure readings is less than 120 mm hg and the diastolic blood pressure is less than 80mm hg, the individual has hypotension.
Which vein is commonly used for administration of medication, transfusions, or obtaining blood samples.
Median cubital vein
Explain how the azygos system provides collateral circulation.
This is a system if there is an obstruction in the inferior vena cava or hepatic portal vein, the azygos system can return blood from the lower body to the superior vena cava. (azygos vein > inferior vena cava > heart (on the bottom) posterior wall of the torso (hemiazygos and accessory hemiazygos veins) > Superior vena cava > heart (on top) when it says collateral circulation, it means there is more than one way to get to the heart.
Define hypertension:
Hypertension is non-transient, persistent high blood pressure.
What are the damaging effects of untreated hypertension?
Untreated hypertension is a major risk factor for the first and third leading causes of death in the US, heart disease and stroke, respectively.
Hypertension is accompanied by high vascular resistance --> Increased tunica media thickness --> Susceptibility to atherosclerosis and CAD.
High vascular resistance --> Increased afterload --> Ventricular hypertrophy --> Susceptibility to heart failure.
Describe the function of the hepatic portal circulation:
Hepatic portal vein carries nutrient rich blood from the capillaries of gastrointestinal tract to the liver (thus bypassing the systemic circulation ). This blood is contaminated with toxins and bacteria because of it's presence in our ingested food.The liver phagocytose thebacteria, detoxifies the harmful substances and also processes and stores nutrients before letting the blood enter systemic circulation through the portal vein.
Blood from the heart enters the ascending aorta and supplies what vessels on the Left side?
Aortic arch
Left common carotid artery
External carotid artery
Internal carotid artery
Left Subclavian artery
From the Left and Right Subclavian artery where does blood go?
Vertebral artery
Axillary artery
Brachial artery
Radial artery
Ulnar artery
Palmar arches (receives blood from both radial and ulnar arteries)
Digital arteries of the hand
The Aorta supplies blood to what vessels on the right side?
Brachiocephalic trunk (only on right side)
Right common carotid artery
External carotid artery
Internal carotid artery
Right subclavian artery (has sametributaries as left subclavian artery given above)
Which blood vessels act as reservoirs?
Veins and venules.
Baroreceptors are sensitive to:
blood pressure within arteries.
Blood returning to the heart from the lower torso may travel through the:
Inferior vena cava
superior vena cava
Hepatic portal vein
The _________ artery brings blood to the large intestine.
inferior mesenteric artery.
Blood leaves the foot by:
plantar venous arch.
The ________ artery brings blood to the liver, spleen and stomach.
Celiac
The _________ artery brings blood to the small intestine.
superior mesenteric artery.
Autoregulation uses vasodilation or vasoconstriction to adjust blood flow. True or false?
True.
Hypotension is a major risk factor for heart disease. True or false?
False. Hypertension is a major risk factor for heart disease.
A precapillary sphincter is a ring of smooth muscle that regulates the flow of blood into a capillary bed. True or false?
True.
Elastic arteries help move blood during ________ _________.
ventricular relaxation.
The cardiovascular center receives input from higher brain regions and sensory receptors to regulate blood pressure. True or false?
True.
Capillaries and arterioles carry out the exchange of nutrients and oxygen. True or false?
False.
Vertebral arteries carry blood to the thorax. True or False?
False, vertebral arteries carry blood to the brain.
Start by following arterial blood away from the heart:Arteries:
Ascending aorta: HeartAortic arch
Left common carotid artery: Left side of head & neck External carotid artery
Internal carotid artery
Left subclavian artery: Left upper limbs
Vertebral artery
Axillary artery
Brachial artery
Radial artery
Ulnar artery
Palmar arches
Digital arteries of the hand fingers
Brachiocephalic trunk (only on right side)
Right common carotid artery: Right side of head & neck
External carotid artery
Internal carotid artery Right subclavian artery (has same tributaries as left subclavian artery given above)