Topics 7&8: Blood, Heart and Blood Vessels
|
|
||
|
|
Objectives
Blood
1.
What is the function of blood?
2.
What are the
main components and elements of blood?
3.
What is plasma made of?
4.
Describe the
red blood cell in detail, what does it look like,
what does hemoglobin do how long do they survive?
5.
What is the
function of white blood cells? How are they classified?
6.
How and why
does blood clot?
7.
What is the blood type?
8.
What
determines who you can give blood to?
9.
What are
some common blood disorders?
Heart and Blood
Vessels
1.
What
structure provides the pressure to move blood?
2.
What is the
difference in structure and function of veins
arteries and capillaries
3.
What is so
important about the walls of these vessels?
4.
How does the
lymphatic system help maintain blood volume?
5.
Know the structure and function of the heart.
6.
Describe the
two circuits that comprise circulation.
7.
What is
blood pressure and why is it important?
8.
How much
effect can personal lifestyle choices have on
cardiovascular health?
1. A superhighway and a medium of transport.
A. The heart and circulation is a very important organ system.
B. In these chapters we will be looking at blood and then at how blood is moved from one part of the body to another.
C. We have made many technological advances in order to measure what is going with our circulation.
D. Augustus Waller made the first recordings of a beating heart--using his dog
E. Today we use many instruments to analyze the workings of the heart
A. Blood is a liquid consisting of specialized cells.
B. Blood transports: needed substances to the body and waste products to be disposed.
C. Blood regulates: temperature, volume of liquid in the body and pH.
D. Blood defends: Blood prevents against infection.
E. Blood is the medium of transfer for all of these functions.
A. The volume of blood in an adult human is 5-6 liters (about 8% of body mass)
B. Plasma (about 55% of blood volume)
1) The fluid portion of the blood is mostly water.
2) Plasma proteins perform a variety of tasks:
a) Albumin is important in maintaining osmotic balance and transports chemicals such as therapeutic drugs
b) Alpha and beta globulin’s transport lipids and vitamins
c) Gamma globulins function in immune responses
d) Ffibrinogen serves in blood clotting
3) Plasma also contains ions, glucose, lipids, amino acids, vitamins, hormones, and dissolved gases.
1) Erythrocytes (45% of whole blood) are biconcave disks (see fig 7.3)
a) They contain hemoglobin (hem-containing iron, globulin- a protein) that binds with oxygen
b) They also carry some carbon dioxide
2) Leukocytes assist in removing dead or worn out cells and protect us against invading microbes and foreign agents.
a) Leukocytes are derived form stem cells in the bone marrow
b) RBC's outnumber WBC's (Leukocytes) almost 700 to 1
c) WBC's are classified by two major categories
(1) Granulocytes have a
lobed nucleus and stainable granules in the cytoplasm
(a) Neutrophils are “search and destroy” phagocytic cells
(b) Eosinophils participate in allergic responses and attack parasites
(c) Basophils probably participate in inflammation and allergic responses
(2) Agranulocytes have
no visible granules
(a) Monocytes differentiate into the macrophages
(i) Monocytes differentiate into the macrophages
(ii) Lymphocytes (the B and T cells) carry out specific immune responses
D. Platelets
1) These are fragments of megakaryocytes (large cells) produced by bone marrow stem cells.
2) They are short lived (5-9) days but are constantly being replaced
3) They function in blood clotting
E. Hemostasis: Stopping blood loss. One of the most important functions of blood is its ability to limit blood loss following an injury. If this were not the case, you would bleed to death following small injuries. The three stages are of hemostasis are as follows.
1) Vescular spasm: an intense contraction of blood vessels around the injury area
a) The vessels essentially close off, in some cases preventing blood loss and in others minimizing the extent of blood coagulation
2) Formation of a platelet plug
a) Platelets change to a sticky spiky shape
b) They adhere to the vessel walls and to each other, this forms an original plug in an area
c) The signal for this activity is damage to the vessel wall.
3) Blood clotting or coagulation
a) Blood clotting includes at least 12 clotting factors. The three main ones are prothrombin, thrombin and fibrinogen.
b) A series of steps result in a mass of fibrin platelets and trapped red blood cells. These are all squeezed together to make a clot.
4) Once blood loss has stopped, tissue repair will begin.
F. Closing mechanisms
1) In the intrinsic clotting mechanism, internal damage activates a plasma protein that triggers the formation of thrombin, which acts on fibrinogen to form insoluble threads of fibrin that will entrap blood cells and platelets to form a clot
2) In the extrinsic clotting mechanism, blood clotting is triggered by the release of substances outside the blood itself due to damage there: thrombin is the mediator in this mechanism also
A. Hemoglobin, the Oxygen Carrier
1) Only a small amount of oxygen is dissolved in the blood plasmas
2) Most of the oxygen is bound to the heme groups of hemoglobin
B. Factors that affect Oxygen Binding
1) The amount of oxygen bound to hemoglobin changes as conditions in the tissue vary
a) Binding of oxygen is favored by conditions in the lung: abundant oxygen, cooler temperature, and neutral pH.
b) Release of oxygen is favored in the tissues where the oxygen levels are lower, temperatures higher, and pH more acidic
c) Hemoglobin also transports a small amount of carbon dioxide
2) Hemoglobin is made of the globulin (protein), and heme groups
a) Each molecule has four polypeptide chains, each with a heme containing an iron molecule that binds one molecule of oxygen.
b) Oxygenated hemoglobin (oxyhemoglobin) is bright red
5. Life Cycle of Red Blood Cells
A. Red blood cells form from stem cells in the marrow of bones of the skull, vertebrae, sternum ribs, pelvis and the ends of long bones
1) The hormone erythropoietin from the kidneys is the stimulus for stem cell division
2) When mature they have no nuclei but do have enough cell products to live about 120 days
a) Phagocytic cells (macrophages) remove the oldest cells from the bloodstream: amino acids are returned to the blood, iron to the marrow, and heme groups converted to bilirubin.
b) The red cell count remains rather constant at 5.4 million/microliter for males and 4.8 for females
3) The hematocrit is an important measurement relative to the oxygen-carrying capacity of the blood. It ranges from 43%-49% in males and 37%-43% in females. In order to maintain this level your body must produce over 2 million RBC's a second.
4) Need to discuss more of how RBC’s Are recycled by the spleen
B. Some common blood disorders
1) polychythemia: overproduction of RBC's resulting in thickening of blood and high blood pressure.
2) Thrombocytopenia: reduction in number of platelets resulting in easy bruising or bleeding
3) Blood poisoning: is an infection of the blood
4) Mononucleosis: viral infection of lymphocytes
5) Multiple myeloma: uncontrolled production of plasma cells (B cells)
C. Anemia's
1) Anemia develops when the blood chronically delivers too little oxygen to the tissues
2) In iron deficiency anemia, red cells contain to little hemoglobin, usually resulting from an iron poor diet
3) Pernicious anemia is caused by a deficiency of vitamin B12
6.
The cardiovascular System (Heart and Blood Vessels) quiz
A. The cardiovascular system is the body’s internal rapid transport system, for oxygen, nutrients, secretions, and wastes
1) Cardiovascular system components
a) Blood is the liquid medium of transport
b) The heart is the muscular pump that generates the pressure required to move the blood
c) Blood vessels are the distribution tubes of varying diameters
d) The rout of circulation: heart>> arteries>> arterioles>> capillaries>> venules>> veins>> heart
2) Has functional Links with the Lymphatic System
a) Because of the pressure in the cardiovascular system, water and proteins leak out to become part of the interstitial fluid (This is the fluid in-between cells in tissue)
b) The lymphatic system vessels pick up the fluid and return it to the general circulation
A. The heart is a durable pump made mostly of cardiac muscle (myocardium) surrounded by a tough, fibrous sac. (pericardium).
1) Its chambers have a smooth lining (endocardium) composed of connective tissue and endothelium
2) A thick wall, septum, divides the heart into right and left halves
B. Each half of the heart consists of an atrium (receiving) and a ventricle (pumping) separated by an atrioventricular valve.
1) The AV. valve on the right is the tricuspid: the one on the left is the bicuspid, or mitral valve
2) Chordae tendineae connect the AV valve flaps to the papillary muscles
3) Blood exits each ventricle through a semilunar valve
C. Heart muscle cells are serviced by coronary circulation: coronary arteries (subject to clogging in hear disease) branch off the aorta
A. Each half of the heart (atrium and ventricle) functions as pump in either the pulmonary (right) or systemic (left) circuits
B. Pulmonary circuit
1) The path of blood flow: blood form the body tissues enters (via the superior and inferior vena cavae) the right atrium>>>> tricuspid valve??? right ventricle??? right semilunar valve??? pulmonary arteries??? lungs??? pulmonary veins???? left atrium
2) Blood returning form the body tissues is high in carbon dioxide and low in oxygen: these contents are reversed after passage through the lung capillaries
C. Systemic Circuit
1) Blood moves form the left atrium>>> bicuspid valve?? left ventricle?? left semilunar valve?? aorta??? Common carotid to the head, Subclavian to the arms, Thoracic aorta to the trunk diverges into the femoral arteries the supply the legs. From these large structures the pathway branches more.
2) Capillary beds are of two types: in true capillaries (with blood flow controlled by precapillary sphincters) exchange of substances occurs, but in “thoroughfare channels” blood passes directly form arterioles to venules
3) Usually a given volume of blood in either circuit passes through only one capillary bed, to exception is blood form the digestive tract (via the hepatic portal vein) that passes through the liver capillary beds before leaving via the hepatic vein to return to the general circulation
D. Heartbeat: The Cardiac Cycle:
1) The cardiac cycle is a sequence of contraction (systole) and relaxation (diastole)
a) As the atria fill, the ventricles are relaxed
b) Pressure of the blood in the aria forces the atrioventricular valves open, and the ventricles fill as the atria contract.
c) The ventricles contract, the atrioventricular valves close, and blood flows out through the semilunar valves
2) The heat sound “lub” is made by the closing of the AV valves: the “dub” sound is the closure of the semilunar valves.
9. Mechanisms of heart Contraction
A. The Cardiac Conduction system
1) The cardiac conduction system consists of heart muscle cells and noncontractile cells that are self excitatory
2) Because of the interconnection (via intercalated discs) of cardiac muscle cells, they contract as a single unit
3) Excitation for a heartbeat is initiated in the sinoartial (SA) node (cardiac pacemaker): it then passes to the atrioventricular (AV) node and on to the Purkinje fibers which make contact with the muscle cells that result in ventricular contraction
B. Nervous controls Over Hear Rate
1) Sympathetic nerves increase, parasympathetic nerves decrease, heart contractions.
2) Centers for nervous control of the hear lie in the spinal cord and the brain (medulla oblongata)
10. Blood Pressure and Velocity in the Cardiovascular System
1) The force of blood against the vessel walls can be measured as blood pressure
2) Normal systolic pressure is 120mm of Hg: normal diastolic pressure is 80 mm.
3) Blood pressure values give valuable clues on the condition of the vessels and the flow of blood through them
4) Blood pressure drops along the circuits due to energy loss from resistance
B. Blood Velocity
1) Velocity of flow decreases as the diameter of the vessels decreases
2) it is slowest in the capillaries, which provides time for diffusion to occur
11. How Vessel structure Affects Blood Pressure
A. Arteries conduct blood away form the heart
1) Because of their elastic walls, arteries tend to “smooth out” the pressure changes associated with the discontinuous pumping cycle of the heart
2) Because of their large diameters, arteries present little resistance to flow: blood pressure does not decrease very much in them
B. Resistance at Arterioles
1) Arteries branch into smaller arterioles, where the greatest pressure drop occurs
2) the wall of an arteriole has rings of smooth muscle over a single layer of elastic fibers
a) neural and endocrine signals cause changes in arteriole diameter by stimulating the muscle cells in the walls
b) Arterioles serve as control points where adjustments can be made in blood volume distribution
C. Capillaries
1) Capillaries are diffusion zones for exchanges between blood and interstitial fluid
2) A Capillary is the smallest and thinnest tube (red blood cells travel single file) in the path of circulation and is specialized for exchange of substances with interstitial fluid
3) Total resistance is less than in arterioles so the drop in blood pressure is not as great
D. Venules
and Veins
1) Capillaries merge into venules
2) Venules merge into veins
a) Blood pressure and resistance to flow are both low
b) Veins are blood volume reservoirs (50-60% of blood volume) because their walls can distend or contract
c) Skeletal muscles adjacent to veins squeeze the walls to move the blood along on its way back to the heart: valves prevent backflow
E. Roles of Vessels in Controls over Blood Pressure and Blood distribution
1) the medulla oblongata of the Brian monitors signals form various arteries to determine the rate of heartbeat and any changes needed in vessel diameters
a) If the blood pressure increases, the arterioles are instructed to relax (vasodilatation)
b) If the pressure decreases, the diameter of the arterioles decreases (vasoconstriction)
c) Hormones such as epinephrine and angiotensisn assists
2) Local conditions, such as need for more oxygen and nutrients in active skeletal muscle, cause changes in the rate of flow near those tissues
12. Exchange of fluid and solutes at capillaries
A. Capillaries lie very close to nearly every cell in the body
1) Most solutes, such as the respiratory gases, diffuse across the capillary wall
2) Certain
proteins enter or leave by endocytosis or Exocytosis
3) ions pass through pores and spaces
B. Fluid enters and leaves capillaries in response to various types of pressure
1) Blood pressure tends to force fluid out of the capillaries
2) Water also moves into the capillaries in response to osmotic pressure
13. Blood typing quiz
A. All cells of the human body have surface proteins and other molecules that serve as “self” markers
1) the human body also has antibodies that recognize markers on foreign cells as “nonself”
2) An protein marker that promotes a defensive action is called an antigen
B. ABO
Blood typing
1) ABO blood typing is based upon surface markers on red blood cells
a) The
A has A markers: type B has B markers
2) If bloods of certain donors and recipients are mixed, agglutination (clumping) may occur
C. Rh blood typing
1) Rh blood typing is based on the presence Rh+ or absence Rh- of antigen on the red blood cells
2) An Rh- person transfused with Rh+ blood will produce antibodies to the Rh marker
3) There are risks in pregnancy to a second Rh+ child if a Rh_ woman bore a previous child who was also Rh+ and thus left behind some antibodies that can now seep into this second child and cause clumping.
a) In hemolytic disease of the newborn, too many cells may be destroyed and the fetus dies
b) medical treatment (RhoGam) given to the mother after the birth of the first Rh+ baby can inactivate the Rh antibodies
D. Other Applications of Blood typing
1) Because blood groups are determined by genes, they are useful source of information about a person’s genetic heritage
2) Blood samples provide a source of DNA for testing known as DNA fingerprinting
14. Cardiovascular Disorders
A. Cardiovascular disorders include: hypertension, blood pressure is sustained at elevated levels: atherosclerosis, a condition in which lipid deposits build up on the arterial walls and shrink the diameter of the lumen: and stroke, a rupturing of blood vessels in the brain.
B. cholesterol and Cardiovascular disease
1) High blood levels of cholesterol may be due to eating foods high in cholesterol and/or familial hypercholesterolemia
a) Low-density lipoproteins (LDL) carry cholesterol into the arterial walls: high density lipoproteins (HDL) remove it.
b) If platelets become caught on the plaque, a clot may form there (thrombus) and block flow: or the clot may break free and travel the bloodstream as an embolus.
2) Artherosclerotic plaque is a small mass of lipid deposits, calcium salts, and fibrous net that sticks out in to the arterial lumen
C. Other “healthy Heart” issues
1) The more fat on the body, the more capillaries that must develop to service the cells
2) Smoking presents several increased risks
a) Nicotine stimulates the production of epinephrine, which constricts blood vessels, triggering accelerated heartbeat and a rise in blood pressure
b) Carcinogens in cigarette smoke may contribute to plaque development
c) Carbon monoxide binds to hemoglobin, making the heart pump harder to deliver the oxygen.
d) Other risk factors include: hypertension, lack of exercise, diabetes, family history of heart disorders, and increasing age.
15.
Homeostatic imbalances
of Cardiac Output
A. Normally the heart pumps out as much blood in the arteries as returns via the veins
B. Congestive heart failure occurs when the pumping efficiency of the their is no adequate to meet tissue needs.
1) Is usually due to old age, atherosclerosis, persistent high blood pressure or multiple myocardial infarcts
C. Pulmonary congestion occurs because the resistance from the lung bead of capillaries is less than that of the systemic system. The lungs fill up with blood and fluid causing the person to suffocate in their own fluids. Is common in age related deaths.
D. Edema in the feet ankles and fingers occurs when the right side of the heat fails and blood backs up in the systemic system.
16. Lymphatic System
A. the lymphatic system returns excess fluid (lymph) to the bloodstream via transport tubes and participates in the immune response
B. The lymph vascular System
1) The lymph vascular system includes lymph capillaries and lymph vessels
2) It has three functions
a) return water and plasma proteins to blood
b) Transport fats absorbed from the small intestine
c) Transport foreign particles and cellular debris from tissue spaces to lymph notes for disposal
3) Lymph capillaries begin blindly in the tissues of the body: they lead to lymph vessels, which in turn lead to ducts that return the fluid to the bloodstream
4) Lymph vessels, which have smooth muscles in their walls and valves that prevent backflow, lead to collecting ducts that empty into veins in the lower neck
C. Lymphoid Organs and Tissues
1) They contain lymphocytes, infection fighting cells derived form stem cells in the bone marrow
2) The organs and functions include:
a) The lymph nodes (which resident cells) located along the lymph vessels help remove bacteria and cellular debris.
b) The spleen revolves spent RBCs, holds macrophages, and produces red blood cells in human embryos
c) The thymus secretes hormones that regulate the activity of lymphocytes and is a site where they multiply and mature.
d) The tonsils and appendix also contain lymphatic tissue
Possible assignments: things
to think about
1.
How can a worker in a police crime lab determine if the
blood found at a crime scene is human?
2.
How can you explain the fact that persons who die of
heart attach (lack of oxygen to heart muscle) have perfectly adequate amounts
of oxygenated blood in their heart chambers?
3.
the heart is a double pump, detail the path of blood
through the body. Why two separate
pumps?
03
Blood typing website http://www.nobel.se/medicine/educational/landsteiner/index.html
A nice place to practice studying your muscles. http://www.gen.umn.edu/faculty_staff/jensen/1135/webanatomy/wa_muscle/
The following is a link to a page describing the symptoms of a heart attach, have you ever had any of these?
http://www.americanheart.org/Heart/Warning_Signs/index.html
Ok, this chapter has to have this, the home page of the American heart association
http://www.americanheart.org/
Heart sounds and other structures http://www.bu.edu/cohis/cardvasc/testing/hrtsound.htm
Yet again another page on the heart http://sln.fi.edu/biosci/heart.html
Multiple choice questions Click on the letters to see if the answer is correct. If you need to review click on the hyperlinked words in the question or the answers.
1.
Which of the following statements about the blood are
correct?
|
Rev |
A) The blood is a connective tissue and contains cells, fibers and a liquid matrix |
|
Rev |
B) Plasma carbohydrates include Albumin, Globulin and Fibrinogen. All are important in energy storage. |
|
Rev |
|
|
Rev |
D) The blood is mainly plasma with less than a 10% cell component |
|
rev |
E) The blood contains platelets which are short lived structures that function in blood clotting. |
2.
Oxygen transport is a very important function of the
blood. Which of the following
components of blood are matched with their function in oxygen transport.
|
Rev |
Hemoglobin to oxygen transport |
|
Rev |
|
|
Rev |
Serum to oxygen transport |
|
Rev |
Serum to carbondioxide transport |
|
rev |
Blood vessels to oxygen |
3.
|
Click below to see the
question |
||||||
|
key |
||||||
|
|
|||||
|
|
|||||
|
|
|||||
|
|
|||||