week 7 (blood system, blood and lymphatic system)

Question 1

tunica interna*

Answer 1

In Veins

consist of: epithelium (endothelium), basement membrane and valves

function:

epithelium: physical influences on blood flow, secretion of locally acting chemical mediators that influence the contractile state of the vessel’s overlying smooth muscle, and assistance with capillary permeability. and their smooth luminal surface facilitates efficient blood flow by reducing surface friction

basement membrane:provides a support base for the epithelial layer, gives significant tensile strength, yet its properties also provide resilience for stretching and recoil, anchors the endothelium to the underlying connective tissue while also regulating molecular movement, play an important role in guiding cell movements during tissue repair of blood vessel walls.

Valves: regulates blood flow

In Arteries

consist of: epithelium (endothelium), basement membrane, internal elastic lamina

function:

internal elastic lamina: internal elastic lamina is a thin sheet of elastic fibers with a variable number of window like openings that give it the look of Swiss cheese. These openings facilitate dif usion of materials through the tunica interna to the thicker tunica media

Question 2

tunica media*

Answer 2

In Veins

consist of: smooth muscles

function-

smooth muscles: regulate the diameter of the lumen. An increase in sympathetic stimulation typically stimulates the smooth muscle to contract, squeezing the vessel wall and narrowing the lumen

In Arteries

consist of: smooth muscles, external elastic lamina

function-

external elastic lamina: Separates the tunica media from the tunica externa

Question 3

tunica externa*

Answer 3

In Veins

consist of: elastic and collagen fibres

function:

The tunica externa contains numerous nerves and, especially in larger vessels, tiny blood vessels that supply the tissue of the vessel wall. These small vessels that supply blood to the tissues of the vessel are called vasa vasorum

In Arteries

consist of: elastic and collagen fibres

Question 4

arteries*

Answer 4

carry blood away from the heart to other organs

Large, elastic arteries leave the heart and divide into medium-sized, muscular arteries that branch out into the various regions of the body.

Medium-sized arteries then divide into small arteries, which in turn divide into still smaller arteries called arterioles

Question 4

arterioles*

Answer 4

smaller forms of arteries

they will branch out in a tissue to form capillaries

Question 5

capillaries*

Answer 5

thin walls of capillaries allow the exchange of substances between the blood and body tissue

Question 6

venules*

Answer 6

Groups of capillaries within a tissue re - unite to form small veins called venules

Question 7

veins*

Answer 7

are the blood vessels that convey blood from the tissues back to the heart

Question 8

elastic arteries

Answer 8

Elastic arteries are the largest arteries in the body

They help propel blood onward while the ventricles are relaxing. As blood is ejected from the heart into elastic arteries, their walls stretch, easily accommodating the surge of blood. As they stretch, the elastic fibres momentarily store mechanical energy, functioning as a pressure reservoir Then, the elastic fibres recoil and convert stored (potential) energy in the vessel into kinetic energy of the blood.

Aorta

Question 9

muscular arteries

Answer 9

S: Medium-sized arteries

Muscular arteries have a well-defined internal elastic lamina but a thin external elastic lamina.

The tunica externa is of en thicker than the tunica media in muscular arteries

F: muscular arteries are capable of greater vasoconstriction and vasodilation to adjust the rate of blood flow

brachial artery in the arm and radial artery in the forearm

Question 10

what vessel supplies the blood vessels with nutrients and oxygen

Answer 10

capillaries

Question 11

vasoconstricution

Answer 11

An increase in sympathetic stimulation typically stimulates the smooth muscle to contract, squeezing the vessel wall and narrowing the lumen. Such a decrease in the diameter of the lumen of a blood vessel is called vasoconstriction

Question 12

vasodilation

Answer 12

increase in lumen diameter is called vasodilation

Question 13

vasomotor nerves

Answer 13

nerves of the autonomic nervous system that control the diameter of blood vessels. Vasoconstrictor nerves decrease the diameter vasodilator nerves increase it

The vasomotor center (VMC) is a portion of the medulla oblongata. Together with the cardiovascular center and respiratory center, it regulates blood pressure

Question 14

anastomosis

Answer 14

Most tissues of the body receive blood from more than one artery. The union of the branches of two or more arteries supplying the same body region is called an anastomosis

Question 15

collateral circulation

Answer 15

Anastomoses between arteries provide alternative routes for blood to reach a tissue or organ.

If blood flow stops for a short time when normal movements compress a vessel, or if a vessel is blocked by disease, injury, or surgery, then circulation to a part of the body is not necessarily stopped. The alternative route of blood flow to a body part through an anastomosis is known as collateral circulation

Question 16

sinusoids

Answer 16

rregular tubular space for the passage of blood, taking the place of capillaries and venules in the liver, spleen, and bone marrow

Question 17

vascular (venous) sinus

Answer 17

a vein with a thin endothelial wall that has no smooth muscle to alter its diameter.

In a vascular sinus, the surrounding dense connective tissue replaces the tunica media and tunica externa in providing support.

Question 18

bloods reserviors

Answer 18

The largest portion of your blood volume at rest—about 64%—is in systemic veins and venules.

Systemic arteries and arterioles hold about 13% of the blood volume, systemic capillaries hold about 7%, pulmonary blood vessels hold about 9%, and the heart holds about 7%.

Because systemic veins and venules contain a large percentage of the blood volume, they function as blood reservoirs from which blood can be diverted quickly if the need arises.

Question 19

eight general functions of blood*

Answer 19

1. transportation of oxygen and carbon dioxide between cells and lungs
2. transportation of nutrients to and metabolic wastes away from cells
3. transportation of enzymes and hormones to cells
4. regulation of blood Ph via buffers and amino acids
5. regulation of body temp
6. regulation of water content of cells
7. prevention of body fluids loss via the clotting mechanism
8. protection against foreign microbes and toxin

Question 20

describe blood as a tissue

Answer 20

blood is a type of connective tissue

liquid extracellular matrix of blood is plasma which is 91.5% water

Na, K and Ca are produced in the blood

Question 21

plasma

Answer 21

When the formed elements are removed from blood, a straw-colored liquid called blood plasma (or simply plasma).

Blood plasma is about 91.5% water and 8.5% solutes, most of which (7% by weight) are proteins.

Some of the proteins in blood plasma are also found elsewhere in the body, but those confined to blood are called plasma proteins

Plasma protein

produced by liver

Responsible for colloid osmotic pressure. Major contributors to blood viscosity. Transport hormones (steroid), fatty acids, and calcium. Help regulate blood pH.

Question 22

albumin

Answer 22

Smallest and most numerous plasma proteins

Help maintain osmotic pressure, an important factor in the exchange of fluids across blood capillary walls.

Question 23

globulins

Answer 23

Large proteins (plasma cells produce immunoglobulins).

Immunoglobulins help attack viruses and bacteria.

Alpha and beta globulins transport iron, lipids, and fat-soluble vitamins.

Question 23

fibrinogens

Answer 23

Large protein

Plays essential role in blood clotting

Question 24

erythrocyte (RBC)

Answer 24

It is a matured RBC

8um in diameter

no nucleus

transport oxygen from the lungs to body cells and deliver carbon dioxide from body cells to the lungs

Question 25

formation of red blood cells

Answer 25

In order to form blood cells, pluripotent stem cells in red bone marrow produce two further types of stem cells, which have the capacity to develop into several types of cells. These stem cells are called myeloid stem cells and lymphoid stem cells. Myeloid stem cells begin their development in red bone marrow and give rise to red blood cells, platelets, monocytes, neutrophils, eosinophils, basophils, and mast cells. Lymphoid stem cells, which give rise to lymphocytes, begin their development in red bone marrow but complete it in lymphatic tissues Lymphoid stem cells also give rise to natural killer (NK) cells

Question 25

hemoglobin

Answer 25

oxygen-carrying protein

Question 26

iron in relation to blood

Answer 26

Each RBC contains about 280 million hemoglobin molecules. A hemoglobin molecule consists of a protein called globin, composed of four polypeptide chains a ringlike nonprotein pigment called a heme is bound to each of the four chains.

At the center of each heme ring is an iron ion (Fe2+) that can combine reversibly with one oxygen molecule allowing each hemoglobin molecule to bind four oxygen molecules

Question 27

amino acids in relation to blood

Answer 27

Blood flowing through tissue capillaries picks up carbon dioxide, some of which combines with amino acids in the globin part of hemoglobin

Question 28

vitamen B12 in relation to blood

Answer 28

helps synthesis hemoglobins

Question 29

red blood cell production/destruction

Answer 29

1 Macrophages in the spleen, liver, or red bone marrow phagocytize ruptured and worn-out red blood cells.

2 The globin and heme portions of hemoglobin are split apart.

3 Globin is broken down into amino acids, which can be reused to synthesize other proteins.

4 Iron is removed from the heme portion in the form of Fe3+, which associates with the plasma protein transferring, a transporter for Fe3+ in the bloodstream.

5 In muscle fibers, liver cells, and macrophages of the spleen and liver, Fe3+ detaches from transferrin and attaches to an ironstorage protein called ferritin

6 On release from a storage site or absorption from the gastrointestinal tract, Fe3+ reattaches to transferrin.

7 The Fe3+–transferrin complex is then carried to red bone marrow, where RBC precursor cells take it up through receptor-mediated endocytosis for use in hemoglobin synthesis. Iron is needed for the heme portion of the hemoglobin molecule, and amino acids are needed for the globin portion. Vitamin B12 is also needed for the synthesis of hemoglobin.

8 Erythropoiesis in red bone marrow results in the production of red blood cells, which enter the circulation.

9 When iron is removed from heme, the non-iron portion of heme is converted to biliverdin, a green pigment, and then into bilirubin, a yellow-orange pigment.

10 Bilirubin enters the blood and is transported to the liver.

11 Within the liver, bilirubin is released by liver cells into bile, which passes into the small intestine and then into the large intestine.

12 In the large intestine, bacteria convert bilirubin into urobilinoge.

13 Some urobilinogen is absorbed back into the blood, converted to a yellow pigment called urobilin, and excreted in urine.

14 Most urobilinogen is eliminated in feces in the form of a brown pigment called stercobilin, which gives feces its characteristic color.

Question 30

platelets (thrombocytes)

Answer 30

2–4 μm diameter cell fragments that live for 5–9 days; contain many vesicles but no nucleus.

Form platelet plug in hemostasis; release chemicals that promote vascular spasm and blood clotting

Question 31

Granular Leukocyte

neurophils (WBC)

Answer 31

function: phagocytic cell, ingests debris. Contains chemicals which help in defense released when cell dies

%WBC: 60-70

Question 32

Granular Leukocyte

basophils (WBC)

Answer 32

function: contains chemicals which mediate the inflammatory response (eg. histamine)

%WBC:.5-1

Question 33

Granular Leukocyte

eosinophils (WBC)

Answer 33

function: contains chemicals which inhibit the inflammatory response (eg. histaminase)

%WBC: 2-4

Question 34

Arganular leukocyte

Monocytes (WBC)

Answer 34

function: phagocytic cell. becomes a wandering macrophage when it leaves the blood. ingests and digests debris. displays what it has been eating on its cell surface to help with specific immunity

%WBC: 3-8

Question 35

Arganular leukocyte

lymphocytes (B cells/ T cells)

Answer 35

function: responsible for specific immunity. recognized ‘foreign’ substances mediate response to kill and remove

%WBC: 20-25

Question 36

blood capillary network

Answer 36

he smallest of blood vessels, have diameters of 5– 10 μm

Question 37

role of capillaries in maintaining a relatively constant cellular environment

Answer 37

Capillaries are able to diffuse moleculs from the blood into the extra cellular enironment which allows there to be a consist extraceullar enviornement

Question 38

blood hydrostaic pressure (BHP)

Answer 38

is about 35 millimeters of mercury (mmHg) at the arterial end of a capillary, and about 16 mmHg at the capillary’s venous end BHP “pushes” fluid out of capillaries into interstitial fluid

Question 39

blood osmotic pressure (BOP)

Answer 39

The effect of BCOP is to “pull” fluid from interstitial spaces into capillaries

Question 40

interstital fluid hydrostatic pressure (ISHP)

Answer 40

“pushes” fluid from interstitial spaces back into capillaries

Question 41

interstitial fluid osmotic pressure

Answer 41

which “pulls” fluid out of capillaries into interstitial fluid.

Question 42

three main functions of the lymphatic system

Answer 42

1. return of excess tissue fluid, protein and fat to the blood via lymphatic vessels
2. production of lympohocytes, monocytes and plasma cells for body defense by lymph nodes
   
   1. transport of lipids following absorption from small intestine

Question 43

fluid compoent of lympathic system

Answer 43

h

Question 44

what would happen if the lymph movement was obstructed

Answer 44

h

Question 45

valves

Answer 45

thin folds of tunica interna that form flaplike cusps. The valve cusps project into the lumen, pointing toward the heart (Figure 21.5). The low blood pressure in veins allows blood returning to the heart to slow and even back up; the valves aid in venous return by preventing the backflow of blood.

Question 46

lymph

Answer 46

Lymph is the extracellular fluid that flows in lymphatic vessels. It is a liquid connective tissue that consists of several types of cells in a clear liquid extracellular matrix that is similar to blood plasma but with much less protein. The composition of lymph varies from one part of the body to another.

Question 47

leukocyte (WBC)

Answer 47

protect the body from invading pathogens and other foreign substances. There are several types of WBCs: neutrophils, basophils, eosinophils, monocytes, and lymphocytes.

Question 48

hemopoiesis

Answer 48

The process by which the formed elements of blood develop is called hemopoiesis or hematopoiesis. Before birth, hemopoiesis first occurs in the yolk sac of an embryo and later in the liver, spleen, thymus, and lymph nodes of a fetus

Red bone marrow becomes the primary site of hemopoiesis in the last 3 months before birth, and continues as the source of blood cells af er birth and throughout life.

Question 49

source of ISF in lymphnodes

Answer 49

the sequence of fluid flow is

blood capillaries (blood) →

interstitial spaces (interstitial fluid) →

lymphatic capillaries (lymph) →

lymphatic vessels (lymph) →

lymphatic trunks or ducts (lymph) →

junction of the internal jugular and subclavian veins (blood).

Question 50

role of lymphatic capillaries

Answer 50

Lymphatic capillaries have greater permeability than blood capillaries and thus can absorb large molecules such as proteins and lipids. Lymphatic capillaries are also slightly larger in diameter than blood capillaries and have a unique one-way structure that permits interstitial fluid to flow into them but not out.

Question 51

role of the five princple lymphatic trunks

Answer 51

The principal trunks are the lumbar, intestinal, bronchomediastinal, subclavian, and jugular trunks

lumbar trunks drain lymph from the lower limbs, the wall and viscera of the pelvis, the kidneys, the adrenal glands, and the abdominal wall.

The intestinal trunk drains lymph from the stomach, intestines, pancreas, spleen, and part of the liver.

The bronchomediastinal trunks drain lymph from the thoracic wall, lung, and heart.

The subclavian trunks drain the upper limbs.

The jugular trunks drain the head and neck.