2.9 Transport (circulatory + immune system) Flashcards
Adrenaline
a hormone produced by the adrenal glands in response to fear or stress
increases the heart rate and boosts the delivery of blood to the muscles, flight or fight response
Aorta
the main artery that takes oxygenated blood away from the heart
specifically the left ventricle to the rest of the body
Artery
type of blood vessel that carries blood under high pressure, away from the heart to the tissues of the body
most arteries carry oxygenated blood apart from the pulmonary artery
arteries have narrow lumen, thick elastic, muscular and outer layers
Atria
the two chambers at the top of the heart that receive blood from the veins and pump blood to the ventricles
much thinner walls compared to the ventricles due to the distance the blood has to travel and therefore blood does not need high pressure
Blood
a tissue contains red blood cells
white blood cells (phagocytes and lymphocytes)
platelets
plasma
Lymphocyte
a type of white blood cell that produces antibodies that are specific to a pathogen
- bind to and destroy pathogens
cells with a very large nucleus
Phagocyte
a type of white blood cell that engulf and digest pathogens
larger cells with a multi-lobed nucleus
Memory cell
a lymphocyte that can recognise a pathogen previously encountered, either from vaccination or infection, and can produce specific antibodies for that pathogen
Plasma
the liquid component of blood that transports waste products like carbon dioxide, urea and heat and useful products like hormones, dissolved nutrients like glucose and amino acids and antibodies
Platelets
fragments of cells found in blood that are involved in clotting as when exposed to the air it causes the soluble fibrinogen to change to insoluble fibrin which acts as a net, collecting RBCs, forming a clot
Red blood cells
cells found in blood that contains haemoglobin that transports oxygen
they have a biconcave shape to increase surface area so more oxygen can be absorbed
no nucleus and contain haemoglobin so more oxygen can be carried
Coronary heart disease
a disease caused by the build-up of fatty deposits inside the coronary arteries (arteries supplying blood to the heart)
causing them to narrow and reduce blood flow to the heart
resulting in less oxygen and glucose to the heart
reducing aerobic and increasing anaerobic respiration
eventually resulting in a heart attack
Haemoglobin
red protein found in red blood cells that is responsible for transporting oxygen
Heart
the organ that pumps blood around the body in the closed, double circulatory system in humans
Veins
a blood vessel that carries blood at low pressure back to the heart, often deoxygenated apart from the pulmonary vein
contains a wider lumen
thinner elastic
thinner muscular and outer layers
and contains valves
Hepatic artery
artery that supplies the liver with oxygenated blood
Hepatic portal vein
carries blood from the intestine to the liver
high in glucose
Hepatic vein
vein that carries blood away from the liver back to the heart
Pulmonary artery
the artery that takes deoxygenated blood from the heart
specifically the right ventricle to the lungs
What is the pulmonary circulation part of the circulatory system?
deoxygenated blood is pumped to the lungs and oxygenated blood returns back to the heart
What is the systemic circulation part of the circulatory system?
oxygenated blood is pumped to all the other organs of the body and deoxygenated blood returns back to the heart
Where in the brain are the nerve pulses that control the changes in heart rate from?
medulla
What causes the heart rate to increase when doing exercise?
When exercise starts the muscles produce more carbon dioxide in aerobic respiration.
Sensors in the aorta and carotid artery detect this increase
They send nerve impulses to the medulla
The medulla responds by sending nerve impulses along the accelerator nerve
The accelerator nerve increases the heart rate
More blood is supplied to the muscles to meet the demands of increased aerobic
respiration.
What are the characteristics of arteries?
thick outer wall
small lumen
thick layer of muscle and elastic fibres
What are the characteristics of veins?
thin layer of muscle and elastic fibres
large lumen
fairly thin outer wall
semilunar valves
What are the characteristics of capillaries?
very small lumen
wall is one cell thick
Why do arteries have a thicker outer wall?
can transport blood at high pressure without bursting
Why do arteries have a thick layer of elastic tissue?
allows artery to stretch and recoil to keep blood flowing at high pressure
Why do arteries have a thick layer of muscular tissue?
helps to control flow of blood by widening (dilating) and narrowing (constricting)
Why do veins have a fairly thin outer wall?
blood is flowing at a lower pressure so thick wall not needed
Why do veins have a thin layer of muscle and elastic tissue?
wall can contract to keep blood flowing
Why do veins contain semilunar valves?
prevent blood flowing backwards
Why do capillaries have walls that are one cell thick?
short distance for diffusion of substances from blood into tissues
What are the two main types of white blood cell?
Phagocytes
Lymphocytes
What is the role of pathogens?
- recognises pathogen
- binds to pathogen
- engulfs pathogen during the process phagocytosis
- the lysozymes containing enzymes move towards the pathogen
- enzymes break down pathogen
- Useful materials are absorbed
- Waste products are removed from the phagocyte
Definition of a phagocyte
Phagocytes are a type of white blood cell that engulf and digest pathogen that they
encounter.
This process is called phagocytosis.
What is the role of lymphocytes?
- Lymphocytes detect pathogen’s antigens
- Lymphocyte identifies the correct type of antibody to make, which is complementary to the pathogen’s antigen
- Lymphocyte releases large numbers of correct antibody
- Pathogens either clump together resulting in death or the antibodies trigger phagocytes. Some pathogens can even burst.
- Lymphocytes produce cells that produce lots of the antibody very quickly if they detect the same pathogen again. These are called memory cells.
Definition of a lymphocyte
Lymphocytes produce special Y shaped proteins called antibodies
Allow organisms to build up an immunity towards certain diseases
What is the role of antibodies?
attach to proteins on the surface of pathogens called antigens
What are anti-toxins?
Some antibodies are specialised to combat toxins, chemicals released by the pathogen which cause cell damage.
They neutralise the toxins - no longer harmful
