The Heart and Blood Vessles Flashcards
the need for a circulatory system
larger organisms require a circulatory system to transport materials to and
from cells
small organisms such as amoeba, fungi etc have no need for one as diffusion is adequate
diffusion definition
movement of molecules from one area of high concentration to an area of low concentration.
Closed circulatory system
heart pumps blood through a network of vessels
materials are exchanged between the blood and cells through thin walled capillaries
eg: humans, rabbits, earthworm
Advantages of a closed circulatory system
- Blood can be pumped faster, speeds up the delivery and removal of materials (animals can have a higher metabolic rate
- It allows for control over the distribution of blood
Open circulatory system
Heart pumps blood into open ended vessels
blood flows through tissues and bathes cells
blood flows back to heart
Eg: insects and spiders
Parts of Artery and Vein
Collagen
Muscle and elastic fibre
Endothelium
LUMEN
Arteries
carry blood away from heart
blood is under high pressure
thick wall
small lumen
valves absent
Pulses**
blood high in O2
Veins
carry blood to heart
low pressure
large lumen
thick wall
valves
smoothly**
blood low in O2
Capillaries: parts
lumen
endothelium
Capillary
one cell thick
where exchange of materials to the cells (o2, co2, urea)
purpose of valves
to prevent back flow of blood
control direction of blood flow
Blood pressure
is the force the blood exerts against the wall of a blood vessel
The heart location
between two lungs above diaphragm
slightly tilted to the left
protected by rib cage
chest cavity, thoracic
surrounded by pericardium
Atria
pump blood into lower chambers (ventricles)
thin walls as pump blood short distance
Ventricles
pump blood out of the heart - right to the lungs left to the head and body (thick)
what holds valves in place
tendons heart strings
Valves
prevent back flow
tricuspid
bicuspid
semilunar valves (half moons) in pulmonary artery and aorta - prevent blood returning to the heart
LORD
left
oxygenated
right
deoxygenated
deoxygenated blood
blood that’s low in oxygen enters heart through the vena cava
blood enters the right atrium, goes through tricuspid valve to enter right ventricle
blood is forced to the lungs through the semilunar valve in the pulmonary artery
oxygenated blood
oxygenated blood returns to the heart from the lungs
it enters the left atrium through the pulmonary veins
pumped down through the bicuspid valve to left ventricle
blood is pumped out to the body through semilunar valve in aorta
What separates oxygenated and deoxygenated
septum
double circulation
heart is a double pump
pulmonary circuit
systemic circuit
advantages of a double circulatory system
allows oxygenated and deoxygenated blood to be kept separate
ensures that the blood pressure is high enough to reach all parts of the body
single circulatory system.
can only produce low blood pressure around most of the body which restricts activities of an animal
eg:fish
portal system
blood pathway that begins and ends in capillaries
vessels do not connect directly to the heart
Eg: Heptic portal vein
pulmonary circuit
deoxygenated blood pumped from right side of heart to lungs
oxygenated blood returns to left side of the heart
systemic circuit
oxygenated blood pumped from left side of heart to all various parts of the body and returns as deoxygenated blood to the right side of heart
general path of blood
- heart
- arteries
- arterioles
- capillaries (exchange)
- venules
- veins
heart is made of…
cardiac muscle which is involuntary and slow to fatigue
pericardium prevents friction
hepatic portal vein
capillaries on both ends which connects the digestive system to the liver
Ventral surface
front
curved
coronary artery runs from left to right
Dorsal surface
back
flat
systole
id when the heart chambers contract
diastole
is when the heart chambers relaz
SA node
sino atrial node
pacemaker
AV node
atrio ventricular node
Cardiac cycle
refers to events which take place during one heartbeat
What ensures the constant movement of blood
the alternate systole and diastole of the heart muscle
Heartbeat is controlled by…
specialised tissue called sino-atrial node (SA)
pacemaker
pacemaker location
found embedded in the wall of the right atrium near where the superior vena cava enters the heart
factors that affect the rate of heartbeat
exercise
temperature
emotions
shock
drugs
Stages of heart beat 1
- Atrial diastole (atria and ventricles are relaxed— blood enters left and right atrium)
Stage of heartbeat 2.
- Atrial systole (sa node sends electrical impulses across the muscles of both atria
This causes both atria to contract (systole) and pump blood down into ventricles
as impulses pass through atria they reach AV node (bottom of right atrium against septum)
Stages of heart beat 3
Ventricular systole
AV nose passes impulses down through septum to the walls of the ventricles causing them to contract
forces blood out of the heart and into pulmonary artery and aorta
Cardiac blood supply
coronary arteries branch out of the aorta and carry oxygen and nutrients to muscle cells of the heart
—> blockage of coronary arteries, common cause of heart attack (angina)
Pulse
a wave of vibrations taht passes down the walls of the arteries when the aorta expands following a ventricular contraction
Effects of Smoking on circulatory system
major cause of CHD
tobacco contains harmful substances
nicotine (blood pressure)
carbon monoxide (hardens arteries)
smoking increases risk of thrombosis (clot)
Effect of exercise of circulatory system
regular exercise makes heart stronger and more efficient at pumping
improves supply of oxygen to cardiac muscle and reduces blood pressure
Effect of diet on circulatory system
Excessive salt: increases blood volume and pressure
Sat Fat/cholesterol: block arteries
Fibre: reduces absorption of cholesterol and decreases risk of heart disease
Lack of Protein: lowers blood pressure
Lack of iron: anaemia
EXPERIMENT: Dissect, display and identify parts of the heart
- Rinse, board
- distinguish ventral and dorsal
- Identify four major blood vessels
- Locate four chambers (using scalpel)
- Cut open left ventricle (thick wall, strings, bicuspid valve)
- Cut Right ventricle (thin wall, strings, tricuspid valve)
- Cut Atria (thin walls, bicuspid and tricuspid valves)
- Cut pulmonary artery (semilunar valve)
- Cut aorta (semilunar valve, beginning of coronary artery)
- Identify septum
- Used small labels to identify all
- clean and sanitise
EXPERIMENT: to investigate the effect of exercise on the pulse rate of a human
- Locate pulse
- count number of pulses per min at rest
- repeat twice more, calculate average
- walk for five mins and repeat
- briskly walk and repeat
- exercise and repeat
