Week 5: Blood & Blood Vessels Flashcards
What are the 3 layers of blood vessels?
Tunica interna (inner)
Tunica media (middle)
Tunica externa (outer)
What type of lining is tunica interna?
Epithelium or endothelium
What type of lining is tunica media?
Smooth muscle and elastic tissue
What type of lining is tunica externa?
Fibrous tissue
What do larger arteries consist of more of?
Tunica media to absorb pressure waves from the heartbeat
What do arterioles mostly consist of?
Smooth muscle
How do arteries withstand high pressure?
By having thicker walls
What are veins?
Blood vessels that return blood flow to the heart under low pressure
Why do veins have thinner walls?
Due to being less muscle/elastic tissue due to lower pressure
Which vessel will remain open when cut?
Arteries
Which blood vessel will collapse when cut?
Veins
What does some veins possess and why?
Valves, to prevent backflow of blood
How much blood to veins hold?
2/3 of blood
What do the pulmonary arteries carry and where from/to?
Carry de-oxygenated blood away from the heart and to the lungs
What does the pulmonary vein carry and where from/to?
Carries oxygenated blood from the lungs to the heart
What are capillaries?
A single layer of endothelial cells, sitting in a thing basement membrane
What do capillaries allow/unallow to pass?
Allow water and small particles
Dont allow blood cells and plasma protiens
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
At baseline activity what controls the diameter and vol of blood?
The autonomic nervous system, in the vasomotor centre (medulla oblongata)
What 3 factors affects resistance flow?
Diameter, length and viscosity
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
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
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
Which centre changes smooth muscle tone leading to a change in local and systemic BP?
Vasomotor centre
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
7%
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