Blood and vessels Flashcards
5 functions of blood
transport (waste, nutrients, oxygen), temperature regulation, immunity, communication, defense
plasma contents (7)
water, nutrients, electrolytes, proteins (albumin, globulins, fibrinogen), nitrogenous wastes, hormones, gases
what does differential blood count do
show percentage of WBC type in blood sample
normal differential blood count neutrophil
40-60%
normal differential blood count lymphocyte
20-40%
normal differential blood count monocyte
2-8%
normal differential blood count eosinophil
1-4%
normal differential blood count basophil
0.5-1%
normal differential blood count band (young neutrophil)
0-3%
neutrophil levels raised in (5)
bacterial infection, inflammation, haemorrhage, infarction, trauma/surgery/burns
neutrophil levels decreased in
viral infection
lymphocyte levels raised in (5)
viral infections, glandular fever, TB, syphilis, whooping cough
lymphocyte levels decreased in (3)
AIDS, steroid therapy, post chemo/radiotherapy
eosinophil levels raised in (3)
asthma, allergy, parasitic infection
monocyte levels raised in (2)
acute chronic infections (e.g. TB), malignant disease
basophil levels raised in (6)
viral infection, malignancy, haemolysis, post-splenectomy, urticaria, hypothyroidism
histology of platelet (2)
very small, blood clotting
histology of monocyte (2)
macrophage, B shaped nucleus
lymphocyte histology (3)
similar to monocyte, circular nucleus, darker staining
neutrophil histology (2)
big nucleus, multilobed nucleus
basophil histology (4)
2 nuclear lobes, not easily distinguishable, granular, lighter staining
eosinophil histology (4)
2 nuclear lobes, easily distinguishable, granular, darker staining
neutrophils wander in
connective tissues
2 methods of neutrophil bacteria killing
phagocytosis and digestion, bactericidal chemical cloud
neutrophil enzymes catalyse which reaction
respiratory burst
in presence of bacteria, neutrophil lysosomes migrate to cell surface and
degranulate
respiratory burst (neutrophil) - neutrophil rapidly absorbs
oxygen
respiratory burst (neutrophil) - oxygen reduced to
superoxide anions
respiratory burst (neutrophil) - superoxide anions react with hydrogen to produce
hydrogen peroxide
respiratory burst (neutrophil) - chloride ions in tissue fluid form
hypochlorite
respiratory burst (neutrophil) - 3 highly toxic chemicals produced
hypochlorite, hydrogen peroxide, superoxide anions
eosinophils most numerous in
mucous membranes
eosinophils concentrated at sites of (3)
allergy, imflammation, parasitic infection
eosinophils help kill parasites (e.g. tape worms) by producing (2 chemicals, 1 other)
superoxide, hydrogen peroxide, toxic chemicals (e.g. neurotoxin)
eosinophils promote action of which 2 cells
basophils and mast cells
eosinophils secrete enzymes that degrade and limit the action of
histamine (and other inflammatory chemicals)
basophils secrete chemicals that aid the mobility and action of
other leukocytes
basophils secrete (3)
leukotrienes, histamine, heparin
function of leukotrienes
activate and attract neutrophils and eosinophils
functions of histamine (3)
vasodilator, increases blood flow, speeds delivery of leukocytes to area
function of heparin
anticoagulant
5% of circulating blood lymphocytes are (2)
natural killer cells and stem cells
80% of circulating blood lymphocytes are
T cells
15% of circulating blood lymphocytes are
B cells
monocytes are in
blood
monocytes in connective tissues are known as
macrophages
erythrocyte function (2)
oxygen delivery, carbon dioxide transportation
erythrocyte shape
discoidal
erythrocytes doesn’t have (2)
nucleus, organelles
erythrocyte method of ATP production
anaerobic fermentation
2 cytoskeletal proteins in erythrocytes
spectrin, actin
percentage of erythrocyte that is Hb
33%
Hb has which 4 globins
2 alpha chains, 2 beta chains
each Hb chain has
haem group
what does haem group do
binds oxygen to ferrous ion
percentage of carbon dioxide transported by Hb
5%
adult form of haemoglobin
HbA
foetal form of haemoglobin
HbF
HbF has two what chains instead of beta chains
gamma chains
do gamma or beta chains have higher oxygen affinity
gamma
tests for Hb (2)
haematocrit, finger prick test
percentage of HbA which is HbA2
2.5%
HbA2 has what instead of beta chains
delta chains
percentage of HbA which is HbAO
92-94%
percentage fo HbA which is HbA1
6-8%
HbA1 beta chain has additional what
glucose group
erythropoiesis takes how long
~3-5 days
four major developments in erythropoiesis
reduction in cell size, increase in cell number, synthesis of Hb, loss of nucleus and organelles
in erythropoiesis, pluripotent stem cell develops into
erythrocyte colony-forming unit
erythrocyte colony-forming unit has receptors for
erythropoietin
function of erythropoietin
stimulates erythrocyte colony-forming unit to transform into erythroblast (normoblast)
erythrocyte- colony-forming unit transforms into
erythroblast (normoblast)
erythroblasts (normoblasts) multiply and synthesise
Hb
once Hb synthesised, nucleus shrivels and
is discharged from cell
once nucleus is discharged from normoblast with Hb, cell known as
reticulocyte
reitculocyte enters
circulating blood
once in blood, cells from erythropoiesis are known as
mature erythrocytes
multipotent stem cells in red bone marrow are known as
haemocytoblasts
sites of haemopoiesis as embryo (5)
yolk sac (first 8 weeks of development) then to liver, spleen, thymus and bone marrow
sites of haemopoiesis as child (2)
liver and spleen
site of haemopoiesis as adult
red bone marrow
red bone marrow is found in which bones (2)
flat and long bones
myeloid stem cells develop into (2)
RBCs and several classes of WBCs
lymphoid stem cells develop into
lymphocytes
after reticulocytes enter blood stream, how long does it take for complete maturation into mature RBCs
24 hours
erythrocyte life span
100-120 days
after 120 days, what erythrocyte damage is detected by phagocytes
plasma membrane rupture / other damage
types of agglutinogens (2)
A or B
Blood group A has which antigens on RBCs
A antigens
Blood group A has which antibodies in plasma
anti-B
Blood group B has which antigens on RBCs
B antigens
Blood group B has which antibodies in plasma
anti-A
Blood group O has which antigens on RBCs
no antigens
Blood group O has which antibodies in plasma
A and B antigens
Blood group AB has which antigens on RBCs
A and B antigens
Blood group AB has which antibodies in plasma
no antibodies
A and B are
codominant
O is
recessive
Anti-A and Anti-B antibodies are usually what type of antibody
IgM
O individuals can also produce which type of ABO antibodies
IgG
Rh+ is
dominant
Rh- is
recessive
Rh gene is one gene (RHD) located where
chromosome 1
precursor to ABO blood group antigens are
H antigens
Absence of H antigen is similar to which blood group
O
Gene for H antigen where
chromosome 19
ABO locus is where
chromosome 9
macrophages of where (3) play role in recycling RBC components
liver, spleen, bone marrow
during haemolysis, Hb breaks down and alpha and beta chains are filtered by
kidneys
breakdown of Hb, haem group is stripped of iron and converted to
biliverdin
breakdown of Hb, haem group is stripped of iron and converted to biliverdin which is then converted to
bilirubin
bilirubin is released into blood stream and binds to
albumin
bilirubin and albumin transported to liver and excreted as
bile
Haemoglobinuria definition
urine red/brown due to excess RBC breakdown
Haematuria definition
intact RBCs in urine
Haematuria occurs after (2)
kidney damage or damage to vessel along urinary tract
jaundice definition
bile duct blocked/liver unable to absorb bilirubin -> bilirubin diffuses into peripheral tissues –> yellow colour
location of spleen
left hypochondriac region, inferior to diaphragm, posterolateral to stomach.
spleen protected by which ribs
10-12
spleen indentations
gastric area and renal area
spleen of hilum penetrated by (3)
splenic artery, splenic vein, lymphatic vessels
parenchyma of spleen has two types of tissue
red pulp, white pulp
red pulp contains
sinuses gorged with concentrated erythrocytes
white pulp contains
lymphocytes and macrophages aggregated with sleeves along small branches of splenic artery
consequence of splenectomy
more vulnerable to infection
innervation of spleen
splenic plexus
spleen has what type of circulation
open
open circulation meaning
blood squeezes through walls of sheathed capillaries into sinuses
sinus of spleen drain into
larger sinuses
larger sinuses of spleen drain into
splenic vein
splenic vein drains into
hepatic portal vein
splenic artery branches
repeatedly through parenchyma
larger arteries of spleen surrounded by
fibrocollagenous sheath
fibrocollagenous sheath of spleen disappears in
smaller branches
smaller branches of spleen form
smaller arterties
smaller arteries of spleen give off
number of short branches at right angles
short branches given off by smaller arteries are known as
penicilliary arteries
penicilliary arteries end in
sheathed capillaries
sheathed capillaries of spleen have
blind-ending
yellow bone marrow develops
adipose tissue
5 mechanisms of venous return to the heart
pressure gradient, gravity, skeletal muscle pump, thoracic (respiratory pump), cardiac suction
venous pressure gradient favours blood flow in which direction?
back towards heart
pressure gradient and venous return increase when (2)
blood volume increases and general widespread vasoconstriction
Skeletal muscle pump –> in limbs, veins are … and … by muscles
surrounded and massaged
Skeletal muscle pump - contracting muscles squeeze blood out of compressed part of vein - what ensures blood flow in only one direction?
valves
thoracic (respiratory) pump aids flow of venous blood from… to …
from abdominal to thoracic cavity
cardiac suction happens during
ventricular systole
during ventricular systole, chordae tendinae of AV valves pull cusps, expanding atrial space. This creates
suction which draws blood from venae cavae and pulmonary veins
define circulatory shock
cardiac output insufficient to meet body’s metabolic needs
two types of circulatory shock
cardiogenic shock, low venous return shock
cardiogenic shock caused by
inadequate pumping of heart
3 main types of low venous return shock
hypovolemic shock, obstructed venous return shock, venous pooling (vascular) shock
definition of low venous return shock
cardiac output low because too little blood returning to heart
most common type of low venous return shock
hypovolemic shock
definition hypovolemic shock
loss of blood volume due to trauma, haemorrhage, bleeding ulcers, burns, dehydration
definition of obstructed venous return shock
when blockage e.g. tumour, aneurysm blocks vein so blood flow is impeded on return to heart
definition of venous pooling (vascular) shock
normal total blood volume but too much blood accumulating in limbs
septic shock definition
bacterial toxins trigger vasodilation and increase capillary permeability
compensated shock definition
body trying to compensate for blood loss
decompensated shock definition
body’s mechanisms unable to continue compensating for blood loss
in compensated shock, hypotension triggers which reflex
baroreflex
in compensated shock, baroreflex triggers production of…
angiotensin II
angiotensin II from baroreflex triggers..
vasoconstriction
in compensated shock, falling or fainting means gravity restores blood flow to
brain
in decompensated shock, myocardial ischaemia and infarction lead to weakened heart and
cardiac output further reduced
in decompensated shock, poor circulation leads to
disseminated intravascular coagulation, congested vessels and therefore reduced venous return
in decompensated shock, ischaemia and acidosis of brainstem lead suppression of … which leads to loss of vasomotor tone > vasodilation > drop in BP > cardiac output reduced
vasomotor and cardiac centres
internal bleeding definition
damage to artery or vein allows blood to collect in surrounding environment
causes of internal bleeding (7)
blunt trauma (compression of internal organs), deceleration trauma (shift of organs upon deceleration), fractures (bone marrow = site of blood production), pregnancy, medication, spontaneous, alcohol abuse
usual treatment of internal bleeding
surgery to repair site of damage and rectify cause
short term cardiovascular response to low blood volume and haemorrhage
elevate BP
long term cardiovascular response to low blood volume and haemorrhage
restoration of blood volume
elevation of BP can be achieved by …. and …. reflexes increased cardiac output and causing peripheral vasoconstriction > increases heart rate
carotid and aortic reflexes
elevation of BP can be achieved by stress and anxiety which stimulate …. nervous system headquarters in hypothalamus
sympathetic
elevation of BP, stimulation of the sympathetic nervous system headquarters triggers further increase in vasomotor tone > constricts arterioles > raises BP. Vasoconstriction mobilises …. which improves ….
venous reserve … venous return
elevation of BP, sympathetic activation stimulates the adrenal medulla to secrete … and …. which increases cardiac output and extends peripheral vasoconstriction
adrenaline and noradrenaline
elevation of BP, sympathetic activation stimulates posterior pituitary to release …. and stimulates production of …. which enhances vasoconstriction
ADH …. angiotensin II
long term cardiovascular response to low blood volume and haemorrhage include
decline in capillary BP (recall of fluid from interstitial spaces) , aldosterone and ADH promote fluid retention and reabsorption at kidneys, thirst increases and digestive tract absorbs additional water, erythropoietin stimulates RBC production
3 signs of shock:
low BP, low body temperature, rapid pulse (often weak and thready)
treatment of shock in hospital (7)
IV (blood or blood products), medication to increase BP and CO, heart monitoring, Swan-Ganz catheterisation, stopping bleeding, blood transfusion or alternatives
Swan-Ganz catheter is what type of catheter?
pulmonary artery catheter
3 uses of Swan-Ganz catheter
detect sepsis and heart failure, monitor effects of drugs and treatment
Swan-Ganz catheter directly measures pressure in (3)
right atrium, right ventricle, pulmonary artery
Swan-Ganz catheter measures wedge pressure of
left atrium (filling pressure)
Swan-Ganz catheter has what type of tip?
balloon
Swan-Ganz catheter can distinguish between what two types of shock
hypovolemic and cardiogenic
Preferred neck site of insertion of Swan-Ganz catheter (4 veins)
Right Internal Jugular > Left Subclavian > Right Subclavian > Left Internal Jugular
Left subclavian vein for Swan-Ganz catheter does not require catheter to
pass course at acute angle to enter superior vena cava
In addition to the neck, Swan-Ganz catheter can be inserted into (2)
wrist, leg (femorally)
what kind of route is used for left heart catheterisation
arterial
what kind of route is used for right heart catheterisation
venous
fractures of lower limb should be considered potential cause of
hypovolemic shock
splintage of fractures can reduce
blood loss
later complications of fractures include (4)
fat embolism, DVT, PE, infection
compartment syndrome definition
bleeding into closed fascial space
compartment syndrome takes up to how many hours to develop
48
compartment syndrome is common in significant ….. fractures although it is possible in …. fractures too
closed; open
compartment syndrome symptoms (5)
pain despite analgesia, extreme pain when moving toes, pallor, pulselessness, paraesthesia
treatment of compartment syndrome (3)
oxygen by mask, fluid into veins, fasciotomy
possible complications of compartment syndrome (6)
permanent nerve damage, permanent muscle damage, permanent scarring, loss of limb, infection, kidney failure
respiratory acidosis from
hypoventilation
respiratory alkalosis from
hyperventilation
respiratory acidosis is due to
imbalance of ventilation-perfusion rates - too much CO2 left in blood stream
respiratory alkalosis is due to
imbalance of ventilation-perfusion rates - too much CO2 removed from body
buffer definition
any mechanism that resists change in pH by converting strong acid/base into weak one
metabolic acidosis can be from (2)
lactic acid production or base loss (e.g. diarrhoea)
metabolic alkalosis is rare but can result from (2)
overuse of bicarbonates or from loss of stomach acid
type 1 respiratory failure oxygen and carbon dioxide levels
low oxygen, normal or low carbon dioxide
type 2 respiratory failure oxygen and carbon dioxide levels
low oxygen, high carbon dioxide
bicarbonate buffer system is a solution of
carbonic acid and bicarbonate ions
bicarbonate buffer system equation
CO2 + H2O H2Co3 HCO3- + H+
phosphate buffer system equation
H2PO4- HPO4(2-) + H+
phosphate buffer system is …. that bicarbonate buffer system
stronger
phosphate buffer system is more important where? why?
renal tubules; closer to optimum pH
renal tubules secrete ……….. into tubular fluid where it binds to ………., ……….. and ……….. > excreted in urines
hydrogen ions; bicarbonate, ammonia, phosphate buffers
hydrogen ions travel in form of ……. and ……
carbonic acid and water molecules
in leukopoiesis, myeloblasts develop into
3 types of granulocytes (neutrophils, eosinophils, basophils)
in leukopoiesis, monoblasts develop into
monocytes
in leukopoiesis, monoblasts look identical to
myeloblasts
in leukopoiesis, lymphoblasts develop into
all types of lymphocyte
in leuokopoiesis, stem cells have receptors for specific ………. which respond to specific needs
colony stimulating factors
tunica intima/interna =
endothelial lining and surrounding layer of connective tissue
in arteries, tunica intima/interna has elastic fibres =
internal elastic membrane
tunica media =
smooth muscle and loose connective tissue
tunica media is bound to tunica interna and tunica externa by
collagen fibres
in small artery, thickest layer is
tunica media
tunica media separated from tunica externa by elastic fibres =
external elastic membrane
tunica externa / adventitia =
connective tissue sheath
in arteries, tunica externa/adventitia made of (2)
collagen and elastic fibres
in veins, tunica externa/adventitia made of (2)
smooth muscle and elastic fibres
thickest layer in veins is
tunica externa/adventitia
elastic arteries are also known as
conducting arteries
in elastic arteries, tunica media is mainly elastic not
muscle
major branches of elastic arteries (2)
aorta, pulmonary trunk
muscular arteries are also known as
distribution arteries
muscular arteries distribute blood to (2)
skeletal muscles and organs
superficial muscular arteries are important as
pressure points (pulses)
arterioles have a poorly defined
tunica externa
arterioles have varying degrees of
smooth muscle
venules collect blood from
capillary beds
smallest venules lack
tunica media
in medium sized veins, tunica media is thin and lacks
muscle
in medium sized veins, the thickest layer is the
tunica externa
in medium sized veins, the tunica externa has
longitudinal bundles of elastic and collagen
large veins have a thick tunica externa made of
elastic and collagen
large veins have slender
tunica media
examples of large veins (2)
venae cavae and tributaries
valves are found in (2)
venules and medium sized veins
capillaries are a ………………………… inside a …………
endothelial tube, thin basement membrane
capillaries have absent (2)
tunica media, tunica externa
continuous capillaries supply
most regions of body
some continuous capillaries have …….. which restrict permeability
tight junctions
fenestrated capillaries have ….. that penetrate endothelial lining which allows rapid exchange between ….. and ….
pores; plasma and interstitial fluid
sinusoids resemble
fenestrated capillaries
sinusoids are flattened and …….. shaped
irregularly
in sinusoids, basement membrane is
thin/absent
entrance to each capillary guarded by
precapillary sphincter
precapillary sphincter controls
where blood flows within plexus
if more than one artery supplies capillary bed they are known as
collaterals
collaterals fuse before arterioles at
arterial anastomoses
direct connections between arterioles and venules are known as
arteriovenous anastomoses
creatinine = waste product of
muscle metabolism
creatinine produced from
creatine
creatinine is filtered out of blood by
kidneys
high creatinine levels lead to reduced
kidney function
hyperkalaemia can indicate
reduced kidney function
hyperkalaemia is when plasma potassium what level
> 5.5mmol/L
blood pressure equation
CO X peripheral resistance
cardiac output definition
volume of blood expelled from heart/min
equation for cardiac output
stroke volume X HR
capillary hydrostatic pressure definition
force exerted by fluid pressing against capillary wall
venous pressure definition
pressure within venous system
total peripheral resistance is affected by (3)
turbulence, blood viscosity, vascular resistance
vascular resistance is affected by friction which is determined by
diameter and vessel length
elastic rebound forces blood towards
capillaries
mean arterial pressure equation
(1/3 pulse pressure) + diastolic pressure
pulse pressure =
systolic - diastolic BP
high BP means …. is 6X more likely
stroke
high BP means … is 3X more likely
cardiac death
high BP means …. is 2X more likely
peripheral arterial disease
secondary hypertension =
cause of hypertension known
primary hypertension =
cause of hypertension unknown
9 risk factors of hypertension
age, family history, african/ caribbean origin, high salt intake, lack of exercise,overweight, smoking, lots of alcohol, stress
4 stages of hypertension
stage 1, stage 2, sever, hypertensive emergency/malignant hypertension
stage 1 hypertension =
BP = 140/90 + ambulatory 135/85
Stage 2 hypertension =
BP = 160/100 + ambulatory 150/95
sever hypertension =
systolic = 180+ / diastolic 110+
hypertensive emergency/ malignant hypertension =
acute impairment of organs, can result in irreversibly damage to organ
rebound hypertension =
when stop taking drugs to reduce BP - 30-50% genetic, 50% environmental
hypertension can lead to fainting because there is an increase in adrenaline binding to … ……. ……… which causes dilation of skeletal muscle arteries and reduction in blood flow and pressure to the brain
beta2- adrenergic receptors
global prevalence hypertension
40%
hypertension more prevalent in younger men than women, but women catch up as get
older
5% CO2 carried in blood as ….. as
dissolved
90% CO2 transported as hydrated
carbonic acid
chloride shift =
chloride into Hb and bicarbonate out via antiport (chloride-bicarbonate exchanger)
oxygen utilisation coefficient usually
~22%
4 factors affecting rate of oxygen unloading
ambient PO2, temperature, Bohr effect, bisphosphoglycerate
temperature and oxygen unloading
higher temp > oxyhaemoglobin dissociation curve shifts to right > increased oxygen unloading
bohr effect and oxygen unloading
more carbon dioxide produced by tissues > increase in hydrogen ions > weakened Hb oxygen bond > increased oxygen unloading
Haldane effect =
low levels of HbO2 > blood transports more carbon dioxide
hypocapnia =
low blood PCO2
hypercapnia =
high blood PCO2
hypoxic drive due to long term
hypoxaemia
hypoxic drive means respiration is driven by
low PO2
hypoxia =
low oxygen reaching tissues
hypoxic hypoxia =
lack of oxygen in blood flow to tissues
hypoxic hypoxia usually due to
inadequate breathing
anaemic hypoxia =
low Hb levels reduce oxygen carrying capacity of blood - many causes
Stagnant (circulatory) hypoxia =
lack of blood flow to tissues
Histiotoxic anaemia =
adequate oxygen inhaled and delivered to tissues, tissues just cannot utilise oxygen
Metabolic hypoxia =
more demand for oxygen by tissues than normal - from raises metabolism e.g. sepsis
5 symptoms of hypoxia
dizziness, dyspnoea, confusion, tachycardia, cyanosis
6 causes of hypercapnia
hypoventilation, diminished consciousness, lung disease, rebreathing exhaled carbon dioxide, exposure to high carbon dioxide environment, initial effect of sleep apnoea > respiratory acidosis
5 symptoms of hypercapnia
hand flaps, flushed skin, hyperventilation, dyspnoea, reduced neural activity
