Transport/Circulation

Physiology 509a with Freeman at Tai Sophia Institute

About this deck

By: Deborah Mizeur
Textbook:

Human Physiology:; An Integrated Approach [HC,2007]
Created: 2010-12-05
Size: 37 flashcards
Views: 23

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Endothelium

Layer of thin epithelial cells that line the lumen of the heart and blood vessels

Vascular smooth muscle

smooth muscle of blood vessels. maintains a state of muscle tone.

Metarterioles

branches of arterioles. regulate blood flow through capillaries and allow white blood cells to go directly from arterioles to the venous circulation. No continuous layer of smooth muscle, so do not dilate. Sphincters on the capillaries open and close as needed to direct flow.

Capillaries and postcapillary venules

site of exchange between blood and interstitial fluid

Angiogenesis

the process by which new blood vessels grow and develop, especially after birth

Arteries

carry blood away from the heart. Pressure in the arteries is created by constricting the heart. Arteries have a lot of elastic tissue, so can handle more pressure.

Arterioles

smaller arteries. Resistance is fairly high. Constriction and dilation begins in arterioles to send blood to various tissues. Local factors in the tissue and long distance control through the sympathetic nervous system determine blood flow.

Capillaries

smallest blood vessel. Final destination of the blood, where all the action of delivering nutrients and removing waste takes place. (figure 15-2). Only endothelium, no smooth muscle or fibers. Endothelium is “leaky” to allow transport of nutrients and waste through the membrane.

Pericytes

make capillaries tighter to slow exchange. Blood brain barrier has many pericytes to tightly regulate exchange.

Venules

very small blood vessels that connect to capillaries, but a little bigger – venule is convergence of capillaries.

Veins

huge reservoir of blood in the body – half of the blood in the body is stored in the veins. Veins have thinner walls than the arteries, not as much smooth muscle or elastic tissue, naturally expand when blood enters. Low pressure. Valves stop the backward flow of blood. Muscle contraction provides pressure to deliver blood back to heart.

Micro-circulation

Arterioles, venules, capillaries

Vasodilation and vasoconstriction

Sympathetic nervious system, local control, hormones

Sympathetic Nervous System

Controls most vascular smooth muscle (circulation). Release norepinephrine to keep vessels tone. When norepinephrine and epinephrine bind to Alpha receptors, vessels constrict.

Myogenic autoregulation

keeps vessels toned. Vessels that have smooth muscle change their own dilation in response to pressure. When blood enters these vessels, they constrict – kind of a reflex – to maintain pressure.

Glycocalyx

mesh of carbohydrate and protein that extends out from the endothelium (almost like hairs reaching out into the blood as it flows by). Serves as a sensor for pressure and other things that are in the blood. When glycocalyx senses increase in pressure, triggers the release of NO (nitrus oxide) to dilate vessel.

Factors that aid venous return to the heart

skeletal muscle pump, one-way valves, low pressure in the thorax during breathing

three paracrines that cause vasodilation

nitric oxide (NO)/endothelium
adenosine/hypoxic cells
histamine/mast cells
<O2,>CO2,>H,>K/cell metabolism

norepinephrine binding to __ receptors causes ___.

alpha, vasoconstriction. alpha receptors are more sensitive to norepinephrine.

epinephrine from the adrenal medulla binds to __ reinforcing __.

alpha receptors, vasoconstriction

Epinephrine binding to beta2 receptors causes ___.

vasodilation

where are beta2 receptors located?

heart, liver, and skeletal muscle arterioles (sympathetic response)

Methods of exchange between capillaries and ISF

Bulk flow (filtration, absorption)
Diffusion
Transcytosis

Bulk flow

the mass movement of fluid between the blood and interstitial fluid. filtration when direction of flow is out of the capillary. absorption if the flow is directed into the capillary.

Diffusion

movement of molecules from an area of higher concentration to an area of lower concentration.

Transcytosis

a combination of endocytosis, vesicular transport across the cell, and exocytosis; used to move macromolecules across an epithelium

Juxtaglomular apparatus

controls blood pressure in the kidney, ensures adequate blood flow into the capillary bed of Bowman’s Capsule. Apparatus uses hormone Renin (produced in the kidney) which forms angiotensinogen which creates angiotensin I, which forms angiotensin II – the most powerful vasoconstricter in the body. ACE inhibitors (Angiotensin Converting Enzymes) block production of angiotensin II

Plasma

fluid portion of the blood, within which cellular elements are suspended. 92% water, 7% proteins, 1% dissolved organic molecules (amino acids, glucose, lipids, nitrogenous wastes), ions (NA+, K+, Cl-, H+, Ca2+, and HCO3-), trace elements and vitamins, and dissolved oxygen and carbon dioxide.

Albumins

Most prevalent type of protein in the plasma (about 60% of the total). Liver makes most plasma proteins and secretes them into the blood.

White Blood Cells (leukocytes)

lymphocytes, monocytes, neutrophils, eosinophils, basophils. Play a key role in the body's immune responses, defending the body against foreign invaders, such as parasites, bacteria, and viruses. Most circulate in the blood, tho their work is usually carried out in the tissues.

Red blood cells

lost their nuclei by the time they enter the bloodstream. play a key role in transporting oxygen from lungs to tissues, and carbon dioxide from tissues to lungs. contain hemoglobin. No mitochondria.

Platelets

cell fragments that have split off a relatively large parent cell known as a megakaryocyte. platelets are instrumental in coagulation.

Macrophage

monocyte that leaves the circulation and enters the tissues

Mast cells

basophils that leave the circulation and enter the tissues

Phagocytes

neutrophils, monocytes, and macrophages. named phagocytes because they can engulf and ingest foreign particles such as bacteria (phagocytosis).

Granulocytes

basophis, eosinophils, and neutrophils. They contaon cytoplasmic inclusions that give them a granular appearance.

Functions of the lymphatic system

1)returning fluid and proteins filtered out of the capillaries to the circulatory system 2)picking up fat absorbed at the sm. intestine and transferring it to the circulatory system 3) serving as a filter to help capture and destroy foreign pathhogens

About this deck

By: Deborah Mizeur
Textbook:

Human Physiology:; An Integrated Approach [HC,2007]
Created: 2010-12-05
Size: 37 flashcards
Views: 23

About StudyBlue

“I have been getting MUCH better grades on all my tests for school. Flash cards, notes, and quizzes are great on here. Thanks!”
Kathy