Blood, The Heart and Blood Vessels, The Lymphatic System Flashcards
blood pressure
the force of blood exerted against the wall of the artery
high pressure in arteries
heart pumping blood through arteries creating higher pressure
low pressure in arteries
blood returning to heart, not being pumped directly by the heart so less pressure
pulse
the expansion and contraction of the arteries due to the pumping action of the heart
portal system
a system that begins and ends in capillaries
diastole
heart chambers relax
systole
heart chambers contract
components of blood
plasma
red blood cells (corpuscles)
white blood cells (leucocytes)
platelets
plasma
liquid part of blood
composition: water, proteins, antibodies, clotting proteins
function: transports dissolved substances (oxygen and lungs) and heat
serum
plasma with no clotting proteins
red blood cells
production site: bone marrow eg ribs
structure: shape is biconcave discs - large surface area for oxygen exchange, shape is flexible for movement through capillaries
life span: 4 months
function: transport oxygen, haemoglobin converts to oxyhaemoglobin at the lungs when it picks up oxygen
when RBCs die
broken down in liver
iron from haemoglobin stored in liver
the rest turned into bile pigments bilirubin and biliverdin
white blood cells
production site: formed in bone marrow and some mature in spleen
structure: nucleus present, no definite shape
less numerous than RBCs
function: defend against disease by killing pathogens
platelets
production site: made in bone marrow
structure: cell fragments, no nucleus
function: forms blood clots (reduce blood loss)
blood type
determined by inherited genes
4 main groups depending on antigen types in RBCs
A , AB, B, O
rhesus factor significance during pregnancy
mother’s blood may make antibodies against babies blood if types are incompatible
blood disorders
anemia
haemophilia
anemia
abnormally low haemoglobin causes: decreased number of RBCs decreased amount of haemoglobin treatment: iron supplements inherited form: sickle cell anemia
haemophilia
the body cannot control it’s ability to clot blood
cause:
inherited (sex linked)
treatment: regular infusion (injecting) of blood clotting factor
open circulatory system
heart pumps blood into vessels that are open ended
eg insects, crabs, snails
closed circulatory system
blood remains in a continuous system of blood vessels
eg humans, caterpillars
advantages:
- blood is pumped faster, cells receive nutrients (glucose, o2) faster
- blood flow to different organs can be changed eg increased blood flow to legs when running
single circulation
blood pumps through the heart once
double circulation
two circuits:
pulmonary: heart-lungs-heart
systemic: heart-body-heart
advantages:
- keeps oxygenated blood separated from deoxygenated blood
- keeps blood pressure high enough to reach all parts of the body
portal system example
hepatic portal vein
connects the stomach and intestines with the liver
only vein that is not connected directly to the heart
blood vessels
arteries
veins
capillaries
arteries
functional difference:
pumps blood away from heart
carry oxygenated blood
structural differences:
thick wall- to withstand great pressure
narrow lumen
no valves- under greater pressure from heart, no need to prevent backflow
veins
functional difference:
pumps blood toward heart
carry deoxygenated blood
how carries out its function:
skeletal muscles contract, squeezing blood through
structural differences:
thin wall- under less pressure
wide lumen
valves present, prevent backflow
capillaries
functional difference:
connect arteries and veins
allows substances to diffuse easily into body cells
structural differences:
walls only one cell thick- allows easier diffusion of substances from blood to body cells
tiny lumen
permeable
the heart
location: between the lungs, slightly to the left side of the thorax, above the diaphragm
function: to pump blood around the body through contraction of cardiac muscle
structure: the heart wall is made of cardiac muscle (does not fatigue)
contractile tissue
can shorten or contract to pump blood
coronary arteries
location: near the semi lunar valves at the aorta
function: supplies heart muscle with blood
coronary vein
removes blood from heart muscle
tricuspid valve location and function
between right atrium and right ventricle
prevents backflow of blood from right ventricle into right atrium
bicuspid valve location and function
between left atrium and left ventricle
prevents back flow of blood from left ventricle into left atrium
semilunar valve location and function
in the aorta and pulmonary artery
prevents backflow of blood into the right and left ventricles
lub dub sound of the heart beat is
valves closing
pacemaker
controls heartbeat
located in the wall at top of right atrium
what controls the rate of heartbeat
brain
cardiac cycle
two pacemakers
1. sinoatrial node (SA)
located in wall of right atrium
role is to generate impulses to cause contraction in the atria
2. Atrioventricular node (AV)
located in septum near tricuspid valve between right atrium and left ventricle
role is to generate impulses to cause contraction in the ventricles
role of SA and AV nodes
generates impulse to cause heart muscles to contract
step 1 of heart beat: atrial and ventricular diastole
blood enters atria
all chambers are relaxed
step 2 of heart beat: atrial systole
electrical impulses sent from SA node, cause atria to contract
blood moves to ventricles
impulse reaches AV node
step 3 of heart beat: ventricular systole
AV node sends impulse to ventricles atria relax ventricles contract semi lunar valves open blood moves into the pulmonary artery and aorta ventricles relax semi lunar valves close
cycle repeats
negative factors that affect the circulatory system
smoking:
- nicotine increases heart rate and pressure
- carbon monoxide reduces o2 in blood
diet:
- salt increases blood pressure
- fats are high in cholesterol, block arteries
positive factors that affect the circulatory system
exercise:
- strengthens the heart, increases circulation
- increases the ability to transport oxygen, provides increased energy levels
differences between circulatory and lymphatic system
lymph: no RBCs, colourless fluid, less wastes and nutrients
blood: RBCs, red fluid, more wastes and nutrients
similarities between circulatory and lymphatic system
tissue fluid produced by plasmid
filtered lymph returns to plasma through capillaries
lymph vessels vs arteries
vessels:
valves
transport lymph
arteries:
no valves
transport blood
function of lymphatic system
returns excess tissue fluid from cells to the bloodstream
origin of lymphatic system
- pressure in arteries can force plasma out of capillaries
- some plasma that does not return becomes tissue fluid, surrounds cells
- this enters the lymphatic system and becomes lymphs
structure of lymphatic system
lymph vessels
lymph nodes
lymph
lymph nodes
structure: swellings in lymph vessels
location: digestive system, groin, armpits, neck
function: filter out any harmful particles from lymph
lymphatic system functions
- collect tissue fluid and return it to the blood system at the subclavian vein
- fight infection by:
- filtering out micro organisms in l nodes
- destroying micro organisms by antibody production
- mature and store lymphocytes - absorbs fat from the small intestine
how fat is absorbed from the small intestine
- fatty acids and glycerol are absorbed into the lacteal
- re-from into fats
- diffuse to bloodstream through blood vessels
white blood cell types
lymphocyte- engulf and digest pathogens
monocyte- become macrophages and directly engulf and digest pathogens
