A&P 2 (blood vessels)

circulatory system

a broad term that encompasses the entire network of organs and vessels responsible for the flow of blood, nutrients, hormones, oxygen, and other gases to and from cells.

Cardiovascular System

This includes the heart and all blood vessels (arteries, veins, and capillaries) that circulate blood throughout the body.

Lymphatic System

Transports lymph, a fluid containing white blood cells and waste products, back into the bloodstream. It also plays a crucial role in the body's immune defense.

circulatory system

the generalized and more specialized functions of transport of materials, capillary exchange, maintaining health by transporting white blood cells and various immunoglobulins (antibodies), hemostasis, regulation of body temperature, and helping to maintain acid-base balance.

blood vessels

The tubes that carries blood through the body.

artery

A blood vessel that carries blood away from the heart, where it branches into ever-smaller vessels.

arterioles

the smallest arteries

capillaries

When the blood travels through the arteries and travel down more branched vessels called___.

They are the Smallest vessels.

Consist of endothelial cells.

Perfusion

Happens in capillaries. The process exchanges gases and other substances between the blood capillaries, surrounding cell, and their tissue fluid.

microcirculation

Flow through capillaries

Endosomes

Contained in capillary cells, They Membrane-bound compartments where the walls are leaky allowing substances to past through.

Involves in sorting, trafficking, and processing.

Continuous Capillaries

It is the most common capillary.

Found in almost all vascularized tissues.

Has complete endothelial lining with tight junction between endothelial cells.

Allows Water, ions, other very small molecules between blood plasma and interstitial tissue.

Not associated with the brain.

Rich in transport vesicles that contribute to endocytosis or exocytosis.

Fenestrated capillary

a type of capillary that has pores (fenestrations) in addition to the tight junctions in the endothelial lining.

Allows larger molecules

Common in small intestines and kidneys

They are also found in the brain. Specifically the Choroid plexus, hypothalamus, pituitary, pineal, and thyroid glands.

Sinusoid capillary

the least common type of capillary.

They are flattened and have extensive intercellular gaps and an incomplete basement membrane.

Have very large openings for plasma proteins and and even cells.

Found in the liver and spleen, bone marrow, lymph nodes, and many endocrine glands.

Capillary Beds

A network of capillary vessels intertwined to form a microcirculatory unit.

Enable tissue perfusion.

Precapillary sphincters

Circular smooth muscle cells that surround the capillary at its origin with the arteriole.

Tightly regulate the flow of blood from arteriole to the capillaries.

Normally closed

thoroughfare channel

A capillary bed are closed, blood flows from the arteriole directly in venous circulation, bypassing the capillary bed.

arteriovenous anastomosis

allows blood to bypass the capillary bed and lead directly to the venous system.

venules

Nutrients and wastes are exchanged, and then combine with other vessels that exit capillaries to form___.

They join to form veins.

The primary site for Emigration or diapedesis.

vein

When small blood vessels that carry blood____, a larger blood vessel that returns blood to the heart

Valves

Located in larger veins. They promote the unidirectional flow of blood towards the heart, preventing backflow towards the capillaries.

Formed by sections of thickened endothelium reinforced with connective tissue, extending into the lumens.

skeletal muscular pump

When the muscle contracts, the inferior Valve closes while the superior Valve opens, pumping blood back towards the heart.

capacitance

The ability to hold blood.

The larger the lumens and thinner walls allows to hold more.

capacitance vessels

Vessels that have large lumens and relatively thin walls of vein.

Vasomotor center

Located in the medulla oblongata. When blood flow needs to redistribute to other portions of the body.

venoconstriction

Sends sympathetic stimulation to the smooth muscles in the walls of the veins

venous reserve

Volume of blood

Systemic arteries

Provides blood that is rich in oxygen to the body’s tissues

systemic veins

The blood returned to the heart through____has less oxygen since much of the oxygen carried by the arteries has been delivered to the cells.

pulmonary arteries

carry blood low in oxygen exclusively to the lungs for gas exchange.

Pulmonary veins

return freshly oxygenated blood from the lungs to the heart to be pumped back out into systemic circulation.

Lumen

a hollow passageway through which blood flows. The most general feature for all types of blood vessels.

vasa vasorum

Small blood vessels that help supply blood to larger vessels through their walls. Found in the Tunica Externia.

tunics

Three distinct tissue layers in the artries and veins.

tunica intima

The innermost layer is composed of epithelial and connective tissue layers directly in contact with blood flow.

Contains smooth muscles to increase blood pressure.

Contains collagenous fibers

endothelium

Lining the tunica intima is the specialized simple squamous epithelium

endothelins

Local chemicals released from the endothelium. They constrict the smooth muscle in the vessel walls to increase blood pressure.

basement membrane

They effectively bind to the endothelium to the connective tissue. Provides strength while maintaining flexibility, and it is permeable, allowing materials to pass through it.

areolar connective tissue

The thin outer layer of the tunica intima. Consists primarily of elastic fibers to provide the vessel with additional flexibility

internal elastic membrane

In larger arteries, there is also a thick, distinct layer of elastic fibers at the boundary with the tunica media.

Tunica media

The substantial middle layer of the vessel wall. It is generally the thickest layer in arteries.

vasoconstriction

Decreases blood flow as the smooth muscle in the walls of the tunica media contracts

vasodilation

The tunica media widens, increasing blood flow as the smooth muscle relaxes

nervi vasorum

Small vascular nerves that regulate vasoconstriction and vasodilatation. They run within the walls of blood vessels.

Located in the Tunica Media

External elastic membrane

Separates the tunica media from the outer tunica externa.

tunica externa

The outer tunic is a substantial sheath of connective tissue composed primarily of collagenous fibers

Elastic fibers are found here as well.

artery

A blood vessel that has a thicker wall. They are surging at a far greater pressure.

Elastic arteries

Those close to the heart that have the thickest walls, containing a high percentage of elastic fibers in all three of their tunics.

Any vessel that is 10 mm in diameter is typically elastic.

Recoil of an artery

A blood surge refers to the artery's elastic ability to return to its original shape following the stretching caused by the increased blood volume during systole.

conducting artery

Also known as an elastic artery. It has a large diameter of the lumen that accepts large volumes of blood.

Muscular arteries

It is located farther from the heart. The surge of blood is dampened.

They play a role in Vasoconstriction.

Less elastic fibers

They branch to distribute to different organs.

Also known as a distributing artery.

arteriole

A very small artery that leads to a capillary.

Have all three tunics, but thinner.

They are also called resistance vessels (pressure drops greatly)

vascular tone

The muscle fibers in arterioles are normally slightly contracted, maintaining a consistent muscle tone.

Vascular anastomoses

Play a vital role in ensuring continuous blood supply to various regions in the body.

Arterial anastomoses

Characterized by alternate pathways called collateral channels.

vascular shunts

Arteriovenous anastomoses in capillaries

Blood flow

The movement of blood through a vessel, tissue, or organ, and is usually expressed in terms of volume of blood per unit of time.

resistance

There are several critical variables that contribute to increasing blood flow throughout the body, as well as factors that slow the flow of fluids

Hydrostatic pressure

the force exerted by a fluid due to gravitational pull, usually against the wall of the container in which it is located.

blood pressure

One form of hydrostatic pressure. The force exerted by blood upon the walls of the blood vessels or the chambers of the heart.

May be measured in capillaries and veins, as well as the vessels of the pulmonary circulation

systemic arterial blood pressure

which is the pressure of blood flowing in the arteries of the systemic circulation

Vascular resistance

the opposition to blood flow offered by the blood vessels.

inversely proportional

Blood flow is_______to resistance

Total peripheral resistance

the resistance to blood flow in the entire cardiovascular system.

influenced by several factors such as blood volume, viscosity, vessel length, diameter of a vessel, and turbulence. Three of these variables, namely, blood volume, viscosity and vessel length, will change slowly in the body.

hypovolemia

Low blood volume, may caused by bleeding, dehydration, vomiting, severe burns, or some medications used to treat hypertension.

Hypervolemia

Excessive fluid volume, may be caused by retention of water and sodium, as seen in patients with heart failure, liver cirrhosis, and some forms of kidney disease.

Viscosity

the thickness of fluids that affects their ability to flow. Directly proportional to resistance and inversely proportional to flow

formed elements

two primary determinants of blood viscosity are ______ and plasma proteins.

vascular tone

the contractile state of the smooth muscle and the primary determinant of diameter and, thus, of resistance and flow.

Turbulence

the irregular and chaotic flow of blood within the vessels

laminar flow

smooth blood flow without interruption

Velocity of Blood Flow

Speed at which blood moves through the cardiovascular system.

systolic pressure

the higher value (typically around 120 mmHg) and reflects the arterial pressure resulting from the ejection of blood during ventricular contraction, or systole.

diastolic pressure

The lower value (usually about 80 mmHg) and represents the arterial pressure of blood during ventricular relaxation, or diastole.

Pulse Pressure

the difference between the systolic pressure and the diastolic pressure. (Systolic/diastolic)

Mean arterial pressure (MAP)

the “average” pressure of blood in the arteries, that is, the average force driving blood into vessels that serve the tissues.

ischemia

insufficient blood flow

hypoxia

inadequate oxygenation of tissues

hypoxemia

refers to low levels of oxygen in systemic arterial blood.

Capillary blood pressure

the pressure of blood within the capillary networks of the body.

Essential for the filtration and exchange of water, nutrients, and waste products between blood and tissues.

Tissue perfusion

the process of delivering blood to capillary beds in biological tissues, is crucial for supplying oxygen and nutrients, and is facilitated by the extensive network of capillaries that ensures efficient exchange between blood and tissues.

bulk flow

Mass movement of fluids into and out of capillary beds requires a transport mechanism to be much more efficient than mere diffusion.

filtration

two pressure-driven mechanisms: volumes of fluid move from an area of higher pressure in a capillary bed to an area of lower pressure in the tissues

reabsorption

the movement of fluid from an area of higher pressure in the tissues into an area of lower pressure in the capillaries

hydrostatic pressure (HP)

The primary force driving fluid transport between the capillaries and tissues

Blood hydrostatic pressure

the force exerted by the blood confined within blood vessels or heart chambers.

capillary hydrostatic pressure (CHP)

the pressure exerted by blood against the wall of a capillary

interstitial fluid hydrostatic pressure (IFHP)

opposing hydrostatic pressure

osmotic pressure

The net pressure that drives reabsorption, the movement of fluid from the interstitial fluid back into the capillaries

blood colloid osmotic pressure (BCOP)

The pressure created by the concentration of colloidal proteins

higher than the interstitial fluid colloid osmotic pressure (IFCOP).

Net OP

calculated by subtracting IFCOP from the BCOP

net filtration pressure (NFP)

represents the interaction of the hydrostatic and osmotic pressures, driving fluid out of the capillary.

Neural Regulation  

This is a Short-term mechanism. plays a critical role in the regulation of vascular homeostasis.

cardioacceleratory centers

One of the Neurological regulations of blood pressure. stimulate cardiac function by increasing heart rate and stroke volume via sympathetic stimulation from the cardiac accelerator nerve.

cardioinhibitory centers

One of the Neurological regulations of blood pressure. Slow cardiac function by decreasing heart rate and stroke volume via parasympathetic stimulation from the vagus nerve.

vasomotor centers

One of the Neurological regulations of blood pressure. Control vessel tone or contraction of the smooth muscle in the tunica media. Changes in diameter affect peripheral resistance, pressure, and flow, which affect cardiac output. Most of these neurons act via the release of the neurotransmitter norepinephrine from sympathetic neurons.

aortic sinuses

A Baroreceptor that is found in the walls of the ascending aorta just superior to the aortic valve.

Carotid sinuses

A baroreceptor that is in the base of the internal carotid arteries

chemoreceptors

short-term regulation of baroreceptor, monitor levels of oxygen, carbon dioxide, and hydrogen ions (pH), also contributing to short-term blood pressure homeostasis.