The Circulatory System Flashcards
REVISE TABLE 8.1 WITH TYPES OF WBCs
three principal fluids of body
- blood
- tissue fluid
- lymph
pH of blood
7.3 to 7.45
main functions of blood
- transport
- protection
transport by blood
- digested food
- oxygen
- carbon dioxide
- excretory material
- distribution of hormones
- distribution of heat
protection by blood
- forms a clot when there is a cut in blood vessels
- WBCs engulf bacteria which may have entered the body
- produces antitoxins and antibodies
components of plasma
water
proteins
inorganic salts
others- glucose, amino acids, fibrinogen, hormones, urea
inorganic salts in plasma
sodium chloride, sodium bicarbonate
where are RBCs produced
ribs, breast bone, ilium of hip girdle
where are RBCs produced in embryo
liver and spleen
RBCs are deficient of
- nucleus- to accommodate more oxygen
- mitochondria- cannot use oxygen for themselves , and glucose
- endoplasmic reticulum- increased flexibility for movement through narrow capillaries
Polycythaemia
abnormally increased number of RBCs
Erythropenia
abnormally decreased number of RBCs
define diapedesis
squeezing of WBCs through capillary walls and into tissues
where are WBCs produced
red bone marrow, lymph nodes, liver and spleen
define Leukemia
cancer of the tissue forming WBCs who number increases at the cost of RBCs.
Leukopenia
abnormal decrease in WBCs
functions of WBCs
- phagocytosis
- inflammation
- formation of antibodies
define phagocytosis
neutrophiles engulf particle-like solid substances, especially bacteria
define pus
mainly composed of dead white blood cells together with the tissue cells destroyed by the bacteria
formation of platelets
some giant cells called megakaryocytes in the red bone marrow
destroyed in the spleen
location of spleen
in the abdomen
chemical that initiates clotting of blood (COAGULATION)
thrombokinase
which vitamin is essential for prothrombin
vit K (fat-soluble)
define antigens
RBCs have special proteins on their surface called antigens. plasma contains antibodies, with respect to the antigen present.
location of the heart
in the centre between two lungs, above the diaphragm
define pericardium
the double-walled membrane protecting and covering the heart. pericardial fluid protects the heart from friction and mechanical injuries
why do ventricles have thick muscular walls
because they have to pump blood to long distances
blood vessels entering the heart
- superior vena cava
- inferior vena cava
- pulmonary vein
blood vessels leaving the heart
- pulmonary artery (right ventricle)
- aorta (left ventricle)
location of coronary artery
arising from base of aorta
myocardial infarction
heart attack
angina pectoris
chest pain due to insufficient supply of blood to heart muscle
function of coronary artery
supply blood to muscles of the heart
four valves in heart
- right atrio-ventricular valve (tricuspid)
- left atrio-ventricular valve (bicuspid)
- pulmonary semilunar valve
- aortic semilunar valves
define chordae tendinae
apices of the flaps of tricuspid valve are held in position by these tendinous chords, arising from muscular projections of the ventricle wall known as papillary muscles
location of pulmonary semilunar valve
opening of right ventricle into the pulmonary artery (3)
location of aortic semilunar valve
point of origin of aorta from left ventricle (3)
steps of heartbeat
atria contracts first, followed by ventricular contraction.
systole- contract
diastole- relax
define joint diastole
at the end of ventricular systole, ventricles start in diastole. at the same time, atria also relaxes. both atria and ventricles are in relaxed state together
location of sino-atrial node
walls of the right auricle, near opening of superior vena cava
location of atrio-ventricular node
near the interauricular septum near the tricuspid valve
location of bundle of HIS
begins from AVN and extends to interventricular septum
define purkinje fibres
bundle of HIS consists of branches of fibres running along the wall of the ventricle, which creates an impulse and conducts it to every part of the heart
define artery
a blood vessel carrying blood away from the heart and towards any organ
characteristics of artery
- thick muscular walls
- narrow lumen
- blood flows in spurts
characteristics of vein
- thin muscular walls
- a wider lumen
- blood flows uniformly
- thin pocket-shaped valves to prevent backflow
characteristics of capillary
- wall has a single layer of squamous epithelial cells
- has no muscles
functions of capillaries
- allow outward diffusion of oxygen into intercellular fluid to tissue cells
- allow inward diffusion of carbon dioxide from intercellular fluid
- allow inward and outward diffusion of substances like glucose, amino acids, urea, hormones
- allow leukocytes to squeeze out through capillary walls
define venule
the smallest united common branch of a capillary
define portal vein
one which starts with capillaries, and also ends in capillaries
hepatic portal system
veins from the stomach and intestines enter the liver as a combined hepatic portal vein. here it breaks into capillaries , and on their reunion, forms hepatic vein which joins the inferior vena cava
use of hepatic portal system
- glycogenesis (excess sugar stored in liver as glycogen)
- deamination (excess amino acids are broken down, nitrogen containing parts are separated, and the remaining is stored as glycogen)
- detoxification
define pulse
alternate expansion and elastic recoil of the wall of the artery during ventricular systole
define blood pressure
the pressure which the blood flowing through the arteries exerts on their walls
normal blood pressure for adults
100-140 mm (systolic)
60-80 mm (diastolic)
hypertension
rise in blood pressure above 140/90
what is tissue fluid
when blood flows in the capillaries of the tissues, plasma and leukocytes leak out through their walls. fluid bathes the cells. cells absorb oxygen from this fluid, and give out CO2 and other wastes
what is lymph
some of the tissue fluid may be reabsorbed into the blood vessels, but most of it enters minute channels called lymph vessels
composition of lymph
- only leukocytes (no RBCs or platelets)
- water
- solids like proteins, fats, carbohydrates, enzymes
functions of lymph
- nutritive
- drainage (excess tissue fluid and proteins back to the blood)
- absorption (fats from intestines are absorbed by lacteals in intestinal villi)
- defence (lymphocytes and monocytes)
example of lymph glands
tonsils on the sides of the neck
location of spleen
in the abdomen, behind stomach, above left kidney
reddish brown in colour
functions of spleen
- blood reservoir, releases stored blood into the stream
- produces lymphocytes
- destroys worn-out RBCs
- in an embryo, produces RBCs
