Bio 112 Anatomy and Physiology Ch. 20 Blood vessels and circulation (Saladin)

Transcytosis

Process in which endothelial cells pick up material on one side of the plasma membrane by pinocytosis or receptor mediated endocytosis, transport the vesicles across the cell, and discharge the material on the other side of the exocytosis.

Hypovolemic shock

Produced by a loss of blood volume as a result of hemorrhage, trauma, bleeding ulcers, burns, or dehydration.

Muscular venules

Receives blood from the postcapillary venules.

Anaphylactic shock

Results from exposure to an antigen to which a person is allergic, such as bee venom.

Aldosterone

Salt retaining hormone that promotes Na+ retention in the kidneys.

Intercellular clefts

Separates the endothelial cells.

Compensated shock

Several homeostatic mechanisms bring about spontaneous recovery.

Metarterioles

Short vessels that link arterioles and capillaries.

Vasa vasorum

Small vessels that nourish the outer half of a larger vessel.

Distributing arteries

Smaller branches that distribute blood to specific organs.

Arterioles

Smallest resistance arteries in the body. They have very little tunica externia.

Vasoactive chemicals

Substances that stimulate vasomotion.

Transient ischemic attacks (TIAs)

Temporary dizziness, loss of vision or other senses, weakness, paralusis, headache, or aphasia.

Flow

The amount of blood flowing through an organ, tissue, or blood vessel in a given time.

Microvasculture (microcirculation)

The arterioles, capillaries, and venules are called this.

Pulse pressure

The difference between systolic and diastolic pressure.

Oncotic pressure

The difference between the COP of blood and tissue fluid.

Angiogenesis

The growth of new blood vessels.

Systolic pressure

The peak arterial BP attained during ventricular contraction.

Hydrostatic pressure

The physical force exerted by a liquid against a surface such as a capillary wall.

Hemodynamics

The physical principles of blood flow are based on pressure and resistance.

Postcapillary venules

The smallest veins. They receive blood from capillaries by the distal ends of the thoroughfare channels.

Basal lamina

Thin protein-carbohydrate layer that surrounds the endothelium and separates it from the surrounding tissue.

Reduced capillary reabsorption

This depends on oncotic pressure. A deficiency in albumin.

Resistance arteries

Too variable in number and location to be given names. They exhibit up to 25 layers of smooth muscle and little elastic tissue.

Arterial anastomoses

Two arteries merge and provide collateral routes of blood supply to a tissue.

Natriuretic peptides

Two peptides secreted by the heart called atrial natriuretic peptide and brain natriuteric peptide. They increase Na+ excretion by the kidneys.

Venous sinuses

Veins with especially thin walls, large lumens, and no smooth muscle. Not capable of vasomotion.

Obstructed venous return shock

When any object, such as a growing tumor, compresses a vein and impedes its blood flow.

Septic shock

When bacterial toxins trigger vasodilation and increased capillary permeability.

Decompensated shock

When several life threatening positive feedback loops occur.

Gravity

When standing or sitting, blood from your head and neck returns to the heart simply by flowing downhill through the large veins.

Venous pooling (vascular) shock

When the body has a normal total blood volume, but too much of it accumulates in the lower body.

Vasodilation

Widening of the blood vessels.

Capillary exchange

two way movement of fluid.

Internal carotid artery

Branches near the angle of the mandible to the brain.

External carotid artery

Branches near the angle of the mandible to the face.

Low venous return (LVR) shock

Cardiac output is low because too little blood is returning to the heart.

Cardiogenic shock

Caused by inadequate pumping by the heart, usually a result of myocardial infarction.

Vasomotion

Changes of the diameter of a blood vessel.

Hypertension

Chronic resting blood pressure that is higher than 140/90.

Hypotension

Chronic resting blood pressure that is low. Could be caused by dehydration, anemia, or other factors when someone is approaching death.

The skeletal muscle pump

Contracting muscles squeeze blood out of the compressed part of the vein and the valves ensure that the blood can only go toward the heart.

Cardiac suction

During ventricular systole, the AV cusps downward from the tendinous cords pulling and this slightly expands the atrial space. This causes a suction that draws blood into the atria from the venae cavae and pulmonary veins.

Arteries

Efferent vessels of the cardiovascular system-carry blood away from the heart.

Pericytes

Elongated tendrils that wrap around the capillary. The contract and regulate blood flow through the capillaries.

Precapillary sphincter

Encircles the entrance to one capillary.

Syncope

Fainting.

Perfusion

Flow per given volume or mass of tissue.

Blood pressure (BP)

Force that the blood exerts against a vessel wall.

Neurogenic shock

Form of venous pooling shock that results from a sudden loss of vasomotor tone, allowing the vessel to dilate.

Atherosclerosis

Growth of lipid deposits in the arterial wall.

Fenestrated capillaries

Has endothelial cells riddled with patches of filtration pores (fenestrations).

Large veins

Have smooth muscles in all three tunics. They are greater than 10 mm in diameter.

Vasomotor center

In the medulla oblongata and exerts sympathetic control over blood vessels throughout the body.

Increased capillary filtration

Increased rate of capillary filtration and accumulation of fluid in the tissues.

Arteriosclerosis

Increasing stiffness of the arteries.

Sinusoids (discontinuous capillaries)

Irregular blood-filled spaces in the liver, bone marrow, spleen, and a few other organs. They conform to the shape of the surrounding tissue.

Tunica interna (tunica intima)

Lines the inside of the vessel and is exposed to the blood. Consists of a simple squamous epithelium called the endothelium.

Carotid bodies

Located near the branch of the common carotid arteries. They are oval receptors that are innervated by sensory fibers of the vagus and glossopharyngeal nerves. They are chemoreceptors that monitor changes in blood composition. They adjust breathing to stabilize blood pH and O2 and CO2 levels.

Mean arterial pressure (MAP)

Mean pressure you would obtain if you took measurements at several intervals.

Capillaries

Microscopic, thin walled vessels that connect the smallest arteries to the smallest veins.

Tunica media

Middle layer of the vessel and is usually the thickest. Consists of smooth muscle, collagen, and sometimes elastic tissue.

Diastolic pressure

Minimum arterial BP occurring during ventricular relaxation between heartbeats.

Medium veins

Most veins with individual names are in this category. Has a tunica interna with an endothelium, basement membrane, loose connective tissue, and sometimes a thin internal elastic lamina.

Vasoconstriction

Narrowing of blood vessels.

Obstructed lymphatic drainage

Obstruction or surgical removal of lymph nodes can interfere with fluid drainage and lead to accumulation of tissue fluid distal to the obstruction.

Continuous capillaries

Occur in most tissues, such as skeletal muscles. Endothelial cells held together by tight junctions and form a continuous tube.

Aortic bodies

One to three chemoreceptors located in the aortic arch near the arteries to the head and arms. Structured similar to carotid bodies and have the same function.

Venous anastomoses

One vein empties directly into another.

Peripheral resistance

Opposition to flow that the blood encounters in vessels away from the heart.

Tunica externa (tunica adventitia)

Outer most layer of a vessel. Consists of loose connective tissue that often merges with neighboring blood vessels, nerves, or organs.

Anastomosis

Point where two blood vessels merge.

Angiotensin II

Potent vasoconstrictor that rises blood pressure.

Central venous pressure

Pressure at the point where the venae cavea enter the heart.

Pressure gradient

Pressure generated by the heart and is the most important force in venous flow.

Antodiuretic hormone

Primarily promotes water retention.

Cerebrovascular accident (CVA)

Also known as a stroke. Sudden death of brain tissue caused by ischemia.

Baroreflex

An autonomic negative feedback response to changes in blood pressure.

Reactive hyperemia

An increase above the normal level of flow.

Circulatory shock

Any state in which cardiac output is insufficient to meet the body's metabolic needs.

Chemoreflex

Autonomic response to changes in blood chemistry, especially in pH and O2 and CO2 concentrations.

Medullary ischemic reflex

Autonomic response to reduced perfusion of the brain. In other words, the medulla oblongata monitors its own blood supply and activates corrective reflexes when it senses a state of ischemia (insufficient perfusion)

Carotid sinuses

Baroreceptors that respond to changes in blood pressure.

Conducting arteries

Biggest in the body. Examples are the aorta, common carotid, and pulmonary trunk.

Arteriovenous anastomosis (shunt)

Blood flows from artery directly into a vein and bypasses the capillaries.

Laminar flow

Blood flows in layers. Faster near the center of a vessel and slower near the vessel walls.

Portal system

Blood flows through two consecutive capillary networks before returning to the heart. This occurs in the kidneys connecting to the hypothalamus.

Capillary beds

10-100 capillaries supplied by a single metarteriole.

Colloid osmotic pressure (COP)

A portion of the osmotic pressure due to protein.

Autoregulation

Ability of tissues to regulate their own blood supply.

Venous pooling

Accumulation of blood when venous pressure is not high enough to override the weight of the blood.

Edema

Accumulation of excess fluid in a tissue. Often shows in the face, fingers, abdomen, or ankles, but can also occur in the internal organs.

Epinephrine and norepinephrine

Adrenal and sympathetic catecholamines bind to adrenergic receptors. It stimulates vasocontriction and rises blood pressure.

Veins

Afferent vessels that carry blood back to the heart.

Thoracic (respiratory) pump

Aids in the flow of venous blood from the abdominal to the thoracic cavity.