1. Anatomy and Physiology
Blood and Circulation
Anatomy and Physiology

2. Blood
Functions:
Transports: oxygen for CR, carbon dioxide away, nutrients, ions, immune cells and antibodies
Distributes heat
I. Blood composition (connective tissue – cells in a liquid matrix - ~6 L/person
A. Liquid = Plasma – 54%
H2O
proteins (clotting, Ab, hormones, osmotic balance)
salts (maintain pH, osmotic balance, need for muscle contraction)

3. Blood Composition Continued
B. Cells
1. RBC’s – 45% (erythrocytes – mainly hemoglobin, have no nucleus or mitochondria so don’t use the O2 they carry)
2. WBC’s – 1% (leukocytes – immunity and platelets – blood clotting)
a. Granulocytes – made in bone marrow, their names are based on stains, non- specific
Neutrophils – phagocytes , 1st reaction
Basophils – histamine producers for inflammation and allergic reactions
Eosinophils - ?? – to fight parasites? Mediate allergic reaction

4. Blood composition Continued Cells
b. Lymphocytes – specific immunity – made in lymph glands, spleen, and thymus
B cells – make antibodies
T cells – Helper – increase B cells and T killers
T cells - Cytotoxic – killers – kill bacteria, viruses, tumors
c. Monocytes – made in bone marrow – phagocytosis – when activated become macrophages
d. Platelets – make thromboplastin, serotonin

5. Blood Composition Continued
Relative Abundance of WBC’s:
Never Let Monkeys Eat Bananas
Leukocytes are recruited and activated by cell damage or foreign tissue
Cytokines (chemical attractors of WBC’s) are released by T helpers causing chemotaxis – cells go to chemicals

6. Blood Formation
Forms in red marrow in flat bones and little in the ends of long bones
Erythropoietin (produced by the kidney controls RBC production)
Low O2 causes release of erythropoietin from kidney – increased RBC production – better oxygen carrying cabability – shuts off release of erythropoietin

7. Blood Clotting – 2-6 minutes
Platelets stick to endothelium only when there is a tear
Platelets produce serotonin (neurotransmitter) which acts on smooth muscle causing it to contract and narrows the vessel so blood flow is shut off to that area
Platelets produce thromoboplastin (enzyme) which cleaves prothrombin (inactive) to thrombin (active)
Thrombin links fibrinogen proteins together (small soluble fibrous proteins) and it become fibrin – which is large fibers that act like a mesh
Fibrin covers over the hole in the bv and traps the RBC’s

9. Blood Types A B, AB A, AB A, O B B, O AB A AND B NONE ALL O Blood Type
Antigens on blood cells
Body will make Ab against
Person can Donate to:
Person can Receive From: A
B, AB
A, AB
A, O B
B, O AB
A AND B
NONE
ALL
Universal recipient O
Universal donor

12. Blood Diseases Anemia – decreased O2 carrying ability
Sickle cell anemia – genetic point mutation in hemoglobin
Aplastic Anemia – cancer – can’t produce RBC’s
Iron Deficiency Anemia
Hemolytic Anemia – blood cells are being destroyed
Polycythemia – bone marrow cancer – make too many RBC’s
Leukemia – over production of WBC’s – immature and don’t work – metatstasize to liver, spleen – use up all metabolic substrates and cause tissue destruction
Thrombus – clot
Emobolus – clot that has broken off – may cause stroke
Hemophilia – lack of a clotting factor – blood clots slowly on internal bleeds – 1 hour vs. 6-8 minutes

13. Parts of the Circulatory System
Heart – pumps blood - ~6000 quarts/day
Blood vessels – pipes blood travel through
Lymphatics – cleanse leaked blood of bacteria, viruses, etc. and rejoins blood vessels where veins enter the hear

14. Heart Parts – From outside to in
Membranes (from outside to inside)
Pericardium – serous membrane – epithelial over areolar with visceral and parietal membranes – protects heart and anchors it to sternum and diaphram
Epicardium – outside connective tissue layers of the heart – can be considered visceral pericardium)
Myocardium – cardiac muscle interwoven with dense fibrous connective tissue
Endocardium – sheet of epithelium surrounding the open cavities (has some connective tissue underlying it

15. Membranes of the Heart

16. Heart Parts Continued Chambers
Atria – two cavities on top – right receives blood from body, left receives blood from the lungs
Ventricles – the inferior and larger cavities – right pumps blood to the lungs, left pumps blood to the body
Septum – divides the heart into right and left

18. Heart Parts continued - Valves
Atrioventricular Valves (AV valves)
Between the atria and ventricles
As the ventricles contract it forces the flap of the valve to close and open during ventricular relaxation
Left valve = bicuspid or mitral valve
Right valve = tricuspid
Semilunars (look like half moons)
Cover the pulmonary and aortic arteries
Open up into the artery
Open when the ventricles are contracting so that blood goes to the body or lungs
Back flow closes them so that blood doesn’t flow back into the heart

21. Path of Blood Through the Heart
Rt. Atrium receives oxygen poor blood from the vena cava.
Flows to the rt. Ventrical through the right AV valve (tricuspid)
Rt. Ventricle pumps to lungs thru pulmonary semilunar valve into the pulmonary arteries.
Blood returns to the heart through the pulmonary veins into the left atrium (oxygen rich blood from the lungs)
Blood flows to left ventricle through left AV valve (bicuspid or mitral valve) and is pumped out to body through the aorta thru the aortic semilunar valve.
Blood circulates to the heart thru coronary arteries - only when it is relaxed

23. Blood Vessel Structure
Basic blood vessel structure:
Internal lining (Tunica Intima)
Epithelium - endothelium
Middle of wall (Tunica Media)
Smooth muscle
Outside (Tunica Externa)
Fibrous connective tissue
Capillaries – just one single cell layer thick for diffusion
Epithelium
Connective
Smooth muscle

24. Circulation Heart → Arteries → Arterioles →
(less lumen and smooth muscle)
Capillaries → Venules → Veins → Heart
(just epithelium)

25. Arteries vs. Veins Arteries More smooth muscle
Smaller lumen due to pressure
A lot of pressure
No valves
Veins
Little smooth muscle
Bigger lumen due to less muscle
Low pressure
Valves
Veins are under low pressure so it is difficult for blood to get back to the heart from the feet – need help:
Valves prevent backflow
Skeletal muscle helps push blood back
Pressure in chest from breathing

26. Blood Pressure
Usually measure the pressure in the brachial artery – measure during ventricular systole and ventricular diastole
Normal b.p. = /75-80
Top # is the systolic pressure, bottom # is the diastolic pressure
Hypertention – sustained b.p. of 140/90 and above – damages epithelial lining and accelerated atherosclerosis

27. What controls resistance in blood vessels?
Kidneys monitor blood volume – if too high - ↑ water output – if too low – retain salt which causes water retention
Blood vessel constriction/dilation
Cold – bv constriction
Fight or flight – stress hormones cause vasoconstriction except to skeletal muscle
If lose blood – vasoconstriction to combat pressure loss
When stand up – pressure drops since it is hard to return blood to the heart against gravity – pressure receptors signal brain to cause vasoconstriction and increase heart rate so blood pressure is maintained
Nitric oxide has been found to be the major regulator of bv relaxation
Alcohol lowers bp
Nictotine raises bp

28. Atherosclerosis

29. Cardiac Cycle and Heart Sounds
1. Relaxing heart (atrial and ventricular diastole )
- AV valves open/ SL valves closed
2. Atrial systole (ventricles still in diastole) – pushes any blood still in atria to ventricles before they contract
- Valves are the same
3. Ventricular systole (atria are relaxing – already contracted)
- AV valves close so blood doesn’t squirt back into the atria, SL open to let blood go to lungs and the body

30. Electricity Thru the Heart
SA (sinoatrial node – pacemaker) gets the signal from the brain and sends the electrical impulse through the atria to the AV (atrioventricular) node. The atria then contract.
AV node delays the impulse – allows atria to finish contracting
AV node sends the pulse down the AV bundle to the bundle branches to the Purkinje fibers in the walls of the ventricles
Heart contracts from the apex up sending blood up and out thru the aorta or pulmonary trunk

32. EKG or ECG – measurement of the electrical wave that sets off muscle contraction
P-wave – preceeds the contraction of the atria
Atria are depolarizing (Na+ is flowing into T-tubules)
QRS wave – preceeds ventricular systole – Ventricles are depolarizing
T wave – the ventricles repolarizing – returning Na and K to normal
Can’t see the atria repolarizing since it is behind the QRS wave
Can tell if heart beats too fast or slow if heart is abnormally large due to overwork by size of waves

33. tachycardia