Week 5: Blood & Blood Vessels Flashcards by Frances Rose

What are the 3 layers of blood vessels?

Tunica interna (inner)
Tunica media (middle)
Tunica externa (outer)

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What type of lining is tunica interna?

Epithelium or endothelium

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What type of lining is tunica media?

Smooth muscle and elastic tissue

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What type of lining is tunica externa?

Fibrous tissue

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What do larger arteries consist of more of?

Tunica media to absorb pressure waves from the heartbeat

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What do arterioles mostly consist of?

Smooth muscle

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How do arteries withstand high pressure?

By having thicker walls

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What are veins?

Blood vessels that return blood flow to the heart under low pressure

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Why do veins have thinner walls?

Due to being less muscle/elastic tissue due to lower pressure

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Which vessel will remain open when cut?

Arteries

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Which blood vessel will collapse when cut?

Veins

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What does some veins possess and why?

Valves, to prevent backflow of blood

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How much blood to veins hold?

2/3 of blood

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What do the pulmonary arteries carry and where from/to?

Carry de-oxygenated blood away from the heart and to the lungs

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What does the pulmonary vein carry and where from/to?

Carries oxygenated blood from the lungs to the heart

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What are capillaries?

A single layer of endothelial cells, sitting in a thing basement membrane

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What do capillaries allow/unallow to pass?

Allow water and small particles
Dont allow blood cells and plasma protiens

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What does sympathetic stimulation do?

Determines diameter of the lumen, decreased activity will relax smooth muscle causing vasodilation, increase activity thickens tunica media causing vasoconstriction

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At baseline activity what controls the diameter and vol of blood?

The autonomic nervous system, in the vasomotor centre (medulla oblongata)

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What 3 factors affects resistance flow?

Diameter, length and viscosity

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What happens when the cardio-accelerators centre is stimulated?

Nerve impulse travels along the sympathetic fibres to SA/AV nodes , non-ephinephrine is released increasing heart rate and contractility

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What happens when the cardio-inhibitory centre is stimulated?

Nerve impulses travel along the parasympathetic fibres to SA/AV nodes, acetylcholine is released causing a decrease in heart rate and contractility

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What happens when the vast-motor centre is stimulated?

Nerve impulses travel along sympathetic fibres to blood vessels, nor-epinephrine is released causing vaso-constricction, vast-dilation occurs with decrease stimulation

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Which centre changes smooth muscle tone leading to a change in local and systemic BP?

Vasomotor centre

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What are some examples of auto regulation causing vasodilation?

exercise, excess CO2/hypoxia, tissue damage, inflammation or release of histamine

How is systolic pressure generated?

By ventricular contraction

How is diastolic pressure generated?

By cardiac relaxation

What does PP stand for and how is it calculated?

Pulse pressure, systolic-diastolic

What does MAP stand for and how is it calculated?

Mean arterial pressure, diastolic +1/3 (systolic- diastolic)

What are some factors that can increase blood pressure?

- blood vol increase - heart rate increase - SV increase - peripheral resistance increase - blood viscosity increase

Where is the cardiovascular centre located?

Through the medulla and pons varolli

What does the cardio vascular centre do?

Receives, integrates and coordinates messages from barorecptors, chemoreceptors and from higher centres

What are baroreceptors?

Nerve endings that are sensitive to pressure changes in the vessel, located in the aorta and carotid sinuses

What stimulates baroreceptors?

A rise in BP in the arteries

How do barorecptors decrease BP?

by parasympathetic activity, such as slowing down HR and inhibiting sympathetic stimulation to blood vessels

What does CVC stand for?

Central venous catheter (leads to vena cava)

How does the CVC respond ?

By increasing sympathetic activity (speeding up HR and increasing stimulus to blood vessels)

What are chemoreceptors?

Receptors sensitive to CO2, O2 and blood acidity

Where are chemoreceptors located?

In the carotid and aortic bodies

What are chemoreceptors primarily involved in?

Respiration

What do falls in pH indicate?

Poor tissue perfusion

How is chemoreceptors sympathetic response stimulated?

By increased transportation of O2

What are the higher centres?

- emotional states influencing changes in BP - hypothalamus controlling temp and can respond by adjusting blood vessel diameter

What are some of the functions of blood?

- Providing communication between cells and parts of the body -trasnporting gases/hormones/heat/waste - prevents blood loss -fights toxins - regulates pH

Which side of the system are blood reserves on?

The venous side

What is the nromal pH of blood?

pH 7.35-7.45 (naturally slightly alkaline)

What does CO2 and water mix to form?

Carbonic acid (H2CO3)

What do more hydrogen ions lead to?

Acidosis

What does the blood contain?

Thrombocytes, erythrocytes, leucocytes and plasma

What is plasma mainly made up of?

91% water

How much % of proteins contain fibrinogen

What are erythrocytes and where are they found?

Mature cells that have no nucleus, found in the bone marrow

What is the life span of a erythrocytes?

105-120 days

What do erythrocytes do?

Maintain a primal pH and give blood its viscosity, transport O2 and CO2 between the lungs and the tissue, contain haemoglobin

What are the 5 types of leucocyte/ what do they do?

Neutrophils (micro-organisms), esinophils (de-toxify), basophils (produce heparin), monocytes (ingest and digest) and lymphocytes (form antibodies)

What are thrombocytes/what do they do?

Important for haemostasis of blood clotting, in injury platelets will adhere ti the vessel lining to form a plug stopping the escape of blood into the tissues

What releases thrombokinase?

Platelets, when tissue/blood vessels are damages

What is formed from fibrin+cells?

A clot

What is plasma?

The fluid element of blood which transports the cells, making up 55% of whole blood vol

What does the plasma carry?

Nutrients such as fats and proteins and carbs as well as dissolved O2, CO2 and waste

Which proteins does plasma contain?

- album, globulin, fibrinogen - antibodies - lipids such as cholesterol - electrolytes - enzymes - hormones

What are the ABO blood types

A , B, AB, O

What do type A have?

A antigens, and anti-B antibodies

What do type B have?

B antigens and anit-A antibodies

What does type AB have?

A and B antigens and no anti-A or anti-B antibodies

What does type O have?

No A or B antigens, both anti-A and anti-B antibodies

What does Rh+ have?

Rh antigen on the surface of the RBC

What does Rh- have?

Does not have the Rh antigen

What is the universal donor?

Type O- (due to no A, B or Rh antigens)

What is the universal recipient?

Type AB+ (has all antigens and no anitbodies)

What is an antigen?

A molecule that may be recognised by the immune systems and trigger an immune response by activating leukocytes