Cardiovascular System (Blood Vessels)

What are large veins?

-Adaptations ensure the return of blood to heart despite low pressure -Large-diameter lumens offer little resistance -Venous valves prevent backflow of blood -Most abundant in veins of limbs -Venous sinuses flattened veins with extremely then walls (e.g. coronary sinus of the heart and dural sinuses of the brain)

How does direct renal mechanism work? (kidney)

-Alters blood volume independently of hormones -Increased BP or blood volume causes elimination of more urine. thus reducing BP -Decrease BP or blood volume causes kidneys to conserve water, and BP rises

What is circulatory shock?

-Any condition in which blood vessels are inadequately filled and blood cannot circulate normally -Result in inadequate blood flow to meet tissue needs

What are baroreceptors (response to pressure)?

-Baroreceptors sense changes in BP from vasoconstriction and vasodilation. -quickly adapt to chronic high or low BP so are ineffective -Long-term mechanisms control BP by altering blood volume by using the kidneys

What are arteries?

-Blood vessels that carry blood away from the heart -Except for pulmonary circulation

What are the three important sources of resistance?

-Blood viscosity (the thinner your blood the easier it is to pump, the thicker the harder) -Total blood vessel length (the longer the more force it will take to pump blood) -Blood vessel diameter (The larger the easier to get blood throw the smaller the harder. Older people can have blockage in the vessel in the lumen witch will decrease the size of the diameter)

What are capillaries?

-Capillaries are the exchange vessels. They are microscopic and have only one wall—tunica intima—allowing substances to pass through quickly. -Contact tissue cells; directly serve cellular needs -Found where gas exchange occurred

What are some factor that influences blood pressure?

-Cardiac output (CO) -Peripheral resistance (PR) -Blood volume

What is a vascular shunt?

-Channel that connects arteriole directly with venule -Metarteriole thoroughfare channel

What is the tunica externa (tunica adventitia)?

-Collagen fibers protect and reinforce; anchor to surrounding structures. -Contains nerve fibers, lymphatic vessels -Vasa Vasorum of larger vessels nourishes external layer

Location of the fermoral artery

-Continuation of the external iliac, blood to lower ab. wall, groin, genitals, muscles of thigh -It extends from the iliac artery near the abdomen down to the legs. The primary function of this artery is to supply blood to the lower section of the body. -The femoral artery is located in the thigh and is on the surface of the adductor magnus and longus muscles.

What are some factor that are required to maintain blood pressure?

-Cooperation of heart, blood vessels, and kidneys -Supervision by brain

What is angiogenesis?

-Development of new blood vessels to supply O2 and nutrients -Number of vessels to region increases and existing vessels enlarge -Common in heart when coronary vessel occluded, or throughout body in people in high-altitude areas

What are some characteristics of the Muscular Arteries?

-Distal to elastic arteries -Deliver blood to body organs -Thick tunica media with more smooth muscle -Active in vasoconstriction

What are the reflecting two factors of arteries close to the heart?

-Elasticity (compliance or distensibility) -Volume of blood forced into them at any time -Generate a pulse

when venules converge what happens?

-Formed small veins

What are small veins?

-Have thinner walls, larger lumens compared with corresponding arteries -Blood pressure lower than in arteries -Thin tunica media; thick tunica externa of collagen fibers and elastic networks -Called capacitance vessels (Blood reservoirs) contain up to 65% of blood supply

What are capillary beds?

-Is when all capillaries arterioles branch into the oxygen rich capillaries and then where the oxygen poor capillaries will branch into the venules.

What are some characteristics of the Elastic arteries?

-Large thick-walled arteries with elastin in all three tunics -Aorta and its major branches -Large lumen offers low-resistance -Inactive in vasoconstriction -Act as pressure reservoirs-expand and recoil as blood ejected from heart -Smooth pressure downstream

What are some characteristics of the Capillaries?

-Microscopic blood vessels -Walls of thin tunica intima -In smallest one cell forms entire circumference -Pericytes help stabilize their walls and control permeability -Diameter allows only single RBC to pass at a time

When does long-term autoregulation occurs?

-Occurs when short-term autoregulation cannot meet tissue nutrient requirements -Angiogenesis

What does resistance (peripheral resistance) mean?

-Opposition to flow -Measure of amount of friction blood encounters with vessel walls, generally in peripheral (systemic) circulation

What is Mean Aterial Pressure (MAP)?

-Pressure that propels blood to tissues -MAP=diastolic pressure + 1/3 pulse pressure -Pulse pressure and MAP both decline with increasing distance from heart.

blood flow to lungs

-Pulmonary circuit unusual *pathway short (not really increase in pressure) *arteries/arterioles more like veins/venules (thin walled, with large lumens) *arterial resistance and pressure are low (24/10 mm Hg)

What are precapillary sphincters and how are they regulated?

-Regulate blood flow into true capillaries -Blood may go into true capillaries or to shunt -Regulated by local chemical conditions and vasomotor nerves.

What are some characteristics of the Arterioles?

-Smallest arteries -Lead to capillary beds -Control flow into capillary beds via vasodilation and vasoconstriction

What are venules?

-Smallest veins, collect blood of capillaries after passing through tissues and delivers to venous system -Formed when capillary beds unite. -Allow fluids and WBC's to pass from the bloodstream to tissues. -Large ones have one or two layers of smooth muscle (tunica media).

What is the tunica media?

-Smooth muscle and elastic fiber layer, regulated by the sympathetic nervous system. -Sympathetic vasomotor nerve fibers control (lumen) vasoconstriction and vasodilation of vessels -Influence blood flow and blood pressure

What are some functions of the cardiovascular center?

-They are clusters of sympathetic neurons in medulla oversee changes in CO and blood vessel diameter -Consists of cardiac centers and vasomotor center -Receives inputs from baroreceptors, chemoreceptors, and higher brain centers

What role does the kidney play in BP?

-Your body produces ADH is also called arginine vasopressin which tells the kidney to either retain or release water. It helps with telling your body to either pee or not to pee. -It regulates water to helo with arterial blood pressure. -Direct renal mechanism -indirect renal (renin-angiotensin-aldosterone_ mechanism

What can happen in prolonged hypertension?

-heart failure -vascular disease -renal failure -stroke -also accelerates atherosclerosis (The heart has to work harder-> myocardium enlarges, weakens, become flabby)

What are the purpose of vascular anastomoses?

-is a surgical procedure that is used to connect vessels to each other. Vascular procedures that require an anastomosis include: Coronary artery bypass surgery to treat a blocked artery supplying the heart. Connecting an artery to a vein for hemodialysis access -A vessel is damaged and so you can use another vessel to sustain homeostasis. -Need to increase blood profusion in an area (increase blood flow)

What lining do the capillaries have?

-one single layer of endothelium (thin layer) -allow for diffusion

Blood flow: Skin

-supplies nutrients to cells -helps regulate body temperature -provides a blood reservoir

What are the stages of arteries and vein development?

1. Endothelial lining arises from mesodermal cells in blood islands 2. Blood islands form rudimentary vascular tubes, guided by cues 3. Vascular endothelial growth factor determines whether the vessel becomes artery or vein 4. The heart pumps blood by the 4th week of development

What are some facts about arteries and vein development in fetals?

1. Fetal shunts (foramen ovale and ductus arteriosus) bypass nonfunctional lungs 2.Ductus venosus bypasses the liver 3. Umbilical vein and arteries circulate blood to and from the placenta 4. Congenital vascular problems rare

What is hypertension?

Abnormally high blood pressure * higher than 140 over 90 mmHg (millimeters of mercury). *Prehypertension- if values elevated but not yet in the hypertension range -Common in obese people -temporary/comes and goes: fever, physical exertion, and emotional upset

What is hypotension?

Abnormally low blood pressure: 90 or less.

What are continuous capillaries?

Abundant capillaries in the skin and muscles -Tight junctions connect endothelial cells -Intercellular clefts allow passage of fluids and small solutes Continuous capillaries of the brain - forms the blood brain barrier. -Tight junctions complete, forming blood-brain barrier

What is secondary hypertension?

An uncommon type of hypertension, caused by altered hemodynamics associated with a disease process such as an adrenal tumor, renal problems, etc.

Where will you find capillaries?

Anywhere that need O2

What are the two anastomoses?

Arterial anastomoses Venous anastomoses

What is a venous anastomoses

Arterio-venous anastomoses (AVAs) are direct connections between small arteries and small veins. ... When they are open, they provide a low-resistance connection between arteries and veins, shunting blood directly into the venous plexuses of the limbs.

Why would your blood pressure decrease?

Arteriolar vasodilation Venodilation Decreased cardiac output

common carotid artery

Artery that supplies blood to the face, head, and neck.

Blood flow: Heart

BLOW FLOW TO THE HEAT VIA CORONARY VESSELS: -when activity increases blood flow increase -during ventricular systole -myocardial blood flow ceases -stored myoglobin supplies sufficient oxygen -during diastole high aortic pressure forces blood through the coronary circulation -during strenuous exercise -coronary vessel dilate in response to local accumulation of vasodilators -blood flow will increase

What is pulsatile?

Blood pressure near heart

What are capacitance vessels (can hold a lot of blood due to its elasticity)?

Blood reservoirs that contain 65% of the blood supply.

What are veins?

Blood vessels that carry blood back to the heart

subclavian artery

Both a left and right, blood vessels that supply blood to the shoulders and upper limbs.

Where will you not find capillaries and why?

Cartilage, epithelia (Skin/it is dead), cornea, and lens of eyes because these tissue are avascular (lack of blood vessels no blood flow)

Blood Flow: Skeletal Muscles

Constant at rest, myogenic and general neural mechanisms predominate, During muscle activity, Blood flow increases in direct proportion to the metabolic activity (active or exercise hyperemia), Local controls override sympathetic vasoconstriction, Muscle blood flow can increase 10x or more during physical activity

Blood flow to the brain

Constant should not increase or decrease: - Brain vulnerable under extreme systemic pressure changes -MAP (Mean Arterial Pressure) below 60 mm Hg can cause syncope (fainting) -MAP above 160 mm Hg can result in cerebral edema (swollen)

What are the three structural types of capillaries?

Continuous capillaries Fenestrated capillaries Sinusoid Capillaries (sinusoids)

What is short-term neural and hormonal controls when it comes to blood pressure control?

Counteract fluctuation in blood pressure by altering peripheral resistance and CO -Ex: when you get scared and your brain tells you to release Epinephrine which will cause your heart rate and BH to increase. Short and will come back to normal

What is long-term renal regulation when it comes to blood pressure control?

Counteract fluctuations in blood pressure by altering blood volume (Kidney issues)

What is the arteries from large to small (blood flow from the heart to the largest arteries down to the capillaries)?

Elastic Arteries Muscular Arteries Arterioles Capillaries

What are fenestrated capillaries?

Endothelium that contains "large"-diameter pores (not that large but in molecular context it is) -allow for more absorption/filter to pass-through Function in absorption or filtrate formation (small intestines, endocrine glands, and kidneys)

What is chronic hypotension?

Hint of poor nutrition and warning sign for Addision's disease (adrenal isnsufficiency) or hypothyroidism.

What is the tunica intima?

Innermost endothelium: Inner layer of the blood vessels Lines lumen of all vessels -Continuous with endocardium -Slick surface reduces friction Subendothelial layer in vessels larger than 1 mm; connective tissue basement membrane

celiac trunk

Large unpaired branch of the abdominal aorta that supplies the liver, stomach, and spleen.

What is the different between Lipid-soluble/fat and Water-soluble/protein?

Lipid/fat molecules diffuse directly through endothelial membranes Water/protein has to find a specific pathway

Where does your cardiovascular center located?

Medulla oblongata

What are the factors aiding venous return (blood flow back in veins without the heart being the pump for blood flow)?

Muscular pump Respiratory pump Venoconstriction pump

What is cardiogenic shock?

Occurs when the heart is damaged and unable to supply sufficient blood to the body Pump failure

What is a true capillary?

Part of capillary beds, exchange vessels through capillary bed, branches off the metarteriole

What is an arterial anastomoses

Provide alternate pathways (collateral channels) to give body region -Common at joints, in abdominal organs, brain, and heart; none in retina, kidneys, spleen -Vascular shunts of capillaries are example of arteriovenous anastomoses

inferior mesenteric artery

Supplies arterial blood to the large intestine.

vertebral artery

Supplies blood to the spinal column and brain. -1 of 2 arteries that branch off subclavian arteries, then course up vertebrae into brain

What is the difference between systemic vs arterial blood pressure?

Systemic blood pressure refers to the pressure exerted on blood vessels in systemic circulation, and is often measured using arterial pressure, or pressure exerted upon arteries during heart contractions.

How big are blood vessels?

The closer it is to the heart the larger it is and the farther away the smaller it is.

When talking about systemic blood pressure, where is the highest systemic pressure?

The highest is in the aorta, declines throughout pathway, on the way back to the heart in the right atrium can be 0 mm Hg

Function of the Iliac artery

The internal iliac artery supplies the pelvis, pelvic organs, reproductive organs, and the medial part of the thigh. The external iliac artery is the largest branch of the common iliac artery, and it forms the main blood supply to the lower extremity.

Function of the fermoral artery

The job of the femoral arteries is to deliver oxygenated blood from the heart to the legs and genitals. Once the blood has circulated through, the femoral vein brings the blood (now needing oxygen) back to the heart to circulate through the lungs before being pumped back out to the body through the iliac artery, and eventually the femoral artery and its smaller artery branches.

radial artery

The major artery in the forearm; it is palpable at the wrist on the thumb side.

brachial artery

The major vessel in the upper extremity that supplies blood to the arm.

How does blood flow back to the heart via the veins?

The return of blood to the heart is assisted by the action of the skeletal- muscle pump. As muscles move, they squeeze the veins running through them. Veins contain a series of one-way valves, and they are squeezed, blood is pushed through the valves, which then close to prevent backflow.

What is a pericyte?

They are tiny cells that surround the continuous capillaries that have thin processes that help strengthen the capillary wall without interfering with the flow of particles into or out of the capillary.

What are terminal arteriole?

This is the end of the arterioles path and it will lead into the main metarteriole

What are the three layers in the arteries and veins?

Tunica intima, tunica media, and tunica externa

What are the two types of vessel in the capillary beds?

Vascular shunt True Capillaries

What can sweat causes?

Vasodilation via bradykinn in perspiration -Bradykinin stimulates NO release As temperature decreases, blood is shunted to deeper, more vital organs

Blood flow through capillaries

Vasomotion -Slow, intermittent flow -Reflects on/off opening and closing of precapillary sphincters

What are all the veins from smallest to largest (blood flow from the capillaries bed back to the heart)?

Venules Small veins Large veins

What is the vasa vasorum?

Vessels of the vessels - larger vessels contain this. Nourish the external tissues of the blood vessel wall.

How can you monitor circulatory efficiency?

Vital signs: pulse and BP, along with respiratory rate and body temperature Pulse: pressure wave caused by expansion and recoil of arteries Radial pulse (taken at the wrist) routinely used Pressure point (other areas that you can take a pulse at) where arteries close to body surface -Can be compressed to stop blood flow

What happens to the capillaries when you need a lot of blood flow and when you do not need a lot of blood flow?

When you are needing more blood flow the capillary bed are working at full capacity. When you are not needing a large amount of blood flow then the collateral vessel will be shut off and only have a little amount of blow flow. Ex: digesting vs not digesting, exercising vs sitting

renal artery

an artery originating from the abdominal aorta and supplying the kidneys and adrenal glands and ureters

axillary artery

artery that carries oxygenated blood to the axilla (armpit) area -A large blood vessel that conveys oxygenated blood to the lateral aspect of the thorax, the axilla (armpit) and the upper limb. Its origin is at the lateral margin of the first rib, before which it is called the subclavian artery.

What is tissue perfusion?

blood flow through body tissues at any given time -Delivery of O2 and nutrients to, and removal of wastes from, tissue cells -Gas exchange (lungs) -Absorption of nutrients (digestive tract) -Urine formation (kidneys) Rate of flow is precisely right amount to provide proper function (if you are working out your body needs more O2 to the tissue which can mean an increase of gas exchange)

aortic arch

blood vessels located between ascending and descending aortas that deliver blood to most of the upper body -a curved blood vessel from which arteries branch to the head and neck.

What is a lumen?

central blood-filled space of a vessel

What is a thoroughfare channel?

continuation of the metarteriole that enables blood to bypass a capillary bed and flow directly into a venule, creating a vascular shunt.

Muscular pump

contraction of skeletal muscles "milks" blood toward heart; valves prevent backflow

What is pulse pressure?

difference between systolic and diastolic pressure -throbbing of arteries (pulse)

What are the functions of capillaries?

exchange of gases, nutrients, wastes, hormones, etc., between blood and interstitial fluid

What is blood pressure?

force of blood against arterial walls (mm Hg)

What is autoregulation of blood flow?

how blood flow to an organ remains constant over a wide range of perfusion pressures (automatically)

What is acute (sudden) hypotension?

important sign of circulatory shock; threat for surgical patients and those in ICU

Is the pressure low or high in the capillary and why?

low because of how thin the capillary is high pressure will bust it but also by the time blood flow get farther away from the heart and to the limbs the pressure decrease.

abdominal aorta

lower descending aorta, takes blood to lower trunk and legs -There are five arteries that branch from the abdominal aorta: the celiac artery, the superior mesenteric artery, the inferior mesenteric artery, the renal arteries and the iliac arteries

What is a capillary bed?

network of interconnected capillary vessels that lies between an arteriole and a venule

Respiratory pump

pressure changes during breathing move blood toward heart by squeezing abdominal veins as thoracic veins expand

What is systolic pressure?

pressure exerted on arterial walls during ventricular contraction Average 120 mm Hg in normal adult

What is diastolic pressure?

pressure in the arteries during cardiac relaxation Average 80 mm Hg in normal adult

Why do veins have valves?

prevent back flow of blood -muscular milking

What is vascular shock?

results from extreme vasodilation and decreased peripheral resistance

What is hypovolemic shock?

results from large-scale blood loss

Location of the Iliac artery

right and left external iliac arteries extend from the mid-pelvis to the inguinal ligament as the distal continuation of the common iliac arteries. The common iliac arteries arise from the aortic bifurcation and bifurcate into the external and internal iliac arteries anterior to the sacroiliac joint.

What does the vasomotor center control?

sends steady impulses via sympathetic efferents to blood vessels-> moderate constriction called vasomotor tone (where you are naturally)

What are the two circulations of the Heart ?

systemic circulation and pulmonary circulation

What is orthostatic hypotension?

temporary low BP and dizziness when suddenly rising from a sitting or reclining position

What is a postcapillary venule?

the smallest veins, form when capillaries merge as they exit a capillary bed. This will go into the Venous circuit and take the blood back to the heart

What is blood flow?

the volume of blood flowing through vessel, organ, or entire circulation in a given period (mL)

What run with the veins?

they lymphatic node

Venoconstrication

under sympathetic control pushes blood toward heart

What is bradykinin?

vasodilator

What are sinusoid capillaries?

very "leaky". They have wide-open spaces in the intercellular clefts, and the endothelial cells are fenestrated. They occur whenever there is an extensive exchange of large materials, such as proteins or whole cells. would be the liver, spleen, adrenal medulla. and bone marrow capillaries. They have Macrophages (cells that engulf things that does not belong there) inlining to destroy bacteria