Organisation in animals Flashcards
What is a tissue
Group of similar cell that work together to carry out a particular function. It can include more than one type of cell
What is an organ
A group of different tissues that work together to perform a certain function.
Give 3 types of tissues in mammals
- Muscular tissue: contracts to move whatever it’s attached to e.g. moves stomach walls to churn food
- Glandular tissue: makes and secretes chemicals like enzymes and hormones e.g. makes digestive juices to digest food
- Epithelial tissue: covers some parts of the body e.g. inside of the gut, and outside and inside of the stomach
How does gas exchange happen in the alveoli?
- alveoli surrounded by blood capillaries. This is where gas exchange happens
- blood passing next to the alveoli has returned to the lungs from the rest of the body by the pulmonary artery
- blood coming from body contains lots of carbon dioxide and very little oxygen
-
oxygen diffuses out of the alveolus (higher concentration area) to the blood (lower concentration)
-carbon dioxide diffuse out of the blood(high concentration) into the **alveolus **(low concentration) to be breathed out
What 3 components make up the circulatory system?
- Heart: heart muscle contracts to generate force to move the blood
- Blood vessels: tubular structures that carries blood through all organs and tissues of the body
- Blood: the transport medium that carries nutrients and chemical Messenger molecules(hormones) to the tissues and removes waste products for them
What is a double circulatory system?
The blood passes through the heart twice per complete circuit around the body.
What are the 2 routes in a double circulatory system?
- Pulmonary circuit: deoxygenated blood passes from the left ventricle to the lungs and then returns as oxygenated blood to the left atrium
- Systemic circuit: oxygenated blood passes for the left ventricle to the rest f the body and then returns as deoxygenated blood to the right atrium
Where are the lungs?
Thorax
What is the order in which air travels to the lungs after being inhaled?
trachea, bronchus, bronchiole, alveolus
A blood cell enters the heart through the Vena Cava. Make a flow chart of its journey from there, ending at the aorta. Name the valves in your answer.
vena cava, right atrium, through tricuspid valve, right ventricle, semi-lunar valve, pulmonary artery, lungs, pulmonary vein, left atrium, through bicuspid valve, left ventricle, semi-lunar valve, aorta
What is the heart made of?
- Cardiac muscle tissue
- Nervous tissue
Around the heart, arteries called _____ arteries branch off the _____ and surround the __________ muscle tissue.
coronary, aorta, cardiovascular
What does the pacemaker do?
Controls the natural rate of the heartbeat
Where is the pacemaker located?
The electrical impulses are generated in specialised patch of cells that are located on the right atrium wall
What can be used if a patient has an irregular heartbeat?
an artificial pacemaker
What do artificial pacemakers do?
Artificial pacemakers are electrical devices used to correct irregularities in the heart rate by sending electrical impulses to the heart muscle
Name the three types of blood vessels.
arteries, veins, capillaries
Blood in the arteries is under high pressure, so they need valves. True or False?
False
Veins have valves. True or False?
True
Why do veins need valves?
blood in the veins flows at low pressure and often against gravity, so valves are needed to prevent backflow and pooling
Describe and explain the layers of a vein.
- Thin walls with elastic fibres and muscle: blood pressure is low so valves are present to prevent back flow and pooling of blood
- Wide lumen: reduce resistance between the blood and the walls of the vein
- Irregular lumen
Describe the layers and their functions of the artery wall (including the lumen).
- Walls are made of elastic fibres and smooth muscle
- Thick walls: to withstand high pressure
- Elastic tissue: allows walls to stretch when blood is forced through and recoil when pressure drops
- Narrow lumen- maintain high blood pressure
- Regular and round lumen
Name 4 ways in which capillaries are adapted to their functions.
-
Walls are 1 cell thick
-Permeable walls: substance can diffuse in and out - Lumen same size as red blood cell
- Pores(gaps between cells making up the capillary wall): allow substances to move through
Function of artery?
- carries oxygenated blood at a high pressure away from the heart
Function of vein?
- carries deoxygenated blood at a low pressure towards from the heart
Function of capillaries?
- exchange nutrients e.g. glucose and oxygen from plasma to cells
- exchange of waste products e.g. carbon dioxide from cells to plasma.
rate of blood flow =
Volume of blood / number of minutes
How are red blood cells adapted to their function?
- Biconcave shape: gives larger surface area
- No nucleus: allows more room to carry oxygen
- Contains haemoglobin: binds to oxygen to become oxyhaemoglobin to transport oxygen to lungs and tissue
What is the function of a white blood cell?
Defend the body against microorganisms that cause infection
How can white blood cells perform their function?
- engulf foreign microorganisms through process of phagocytosis and digest them
- produce antibodies: proteins that bind to foreign antigens and destroy them
- produce antitoxins: to neutralise any toxin produced by foreign microorganisms
Description of plasma
Yellow translucent liquid
What is the function of plasma?
- carries:
- red and white blood cells, platelets
- glucose, amino acids : these are soluble products of digestion which are absorbed from the gut and taken to the cells of the body
- carbon dioxide: from organs to the lungs
- urea: from liver to kidneys
- hormones, proteins
- antibodies and antitoxins produced ny white blood cells
What is the description and structure of platelets?
- tiny fragments of cells
- no nucleus
Function of platelets?
- help blood to clot (clump together) at a wound- this seals the wound and stops you from loosing too much blood
- stops microorganisms entering the wound
- lack of platelets can cause excessive bleeding and bruising
what are blood products
components of blood prepared from donated blood - blood tranfusion centres
Advantages of using blood component thearpy:
- more patients can be treated
- the dose of required component can be optimised
- more cost effective + effcient
what is the use of the blood product : Packed red blood cells
- used to restore oxygen carrying capacity
- paitients with anaemia / blood loss
what is the use of the blood product : fresh frozen plasma
treatments for patients with excessive bleeding
what is the use of the blood product : Platelets
treatment / prevention of bleeding in low platelet count patients
what is a stent
metal mesh that insets into the artery to keep lumen open
describe how a stent is inserted into an artery
- catheter used to insert inflated balloon to open up artery
- stent inserted and balloon deflated
- catheter + balloon removed
why would someone have a stent fitted
when artery narrows due to fatty deposits in the artery wall
Advantages of stents:
- lowers risk of heart attack with people with CHD
- operation is quick, effective - patients recover quickly
Disadvantages of stents:
- compilcations can occur during surgery
- risk of infection
- risk of forming blood clot - can lead to stroke / heart attack
what are statins used for
to reduce blood cholesterol levels which slow down rate of fatty material deposit
How do statins work: (LDL + HDL)
-
reducing amount of LDL cholesterol on blood
- LDLs carry fat to artery wall + increase amount of fat deposited
-
Increasing amount of HDL
- HDL carry fat away from artery wall + decrease amount of fat deposited
Advantages of statins:
- reduces risk of strokes, CHD, heart attacks
- may prevent other diseases
Disadvantges of statins:
- must be taken regularly over long period of time
- Negative side effects - headaches, kidney failure
- not immediate effect - takes time for beneficial effect
causes of faulty heart valves:
- heart attack
- infection
- old age
function of heart valves
maintain the blood flow in one direction
consequences of faulty valves:
- breathless - low oxygen supply
- death
- chest pain
what 2 types of valves can faulty valves be replaces with
- biological valves
- mechanical valves
advantages of mechanical valves:
- last a long time
- very effective
- permanent - no need for replacement
- no ethical issues
advantages of biological valves:
- no medication needed
- fully effective
Disadvantages of mechanical valves
- anticoagulants for life (increase risk of blood clotting)
- Open heart surgery needed
- unsuitable for children - cant be still growing
Disadvantages of biological valves
- need replacing after ~15 yrs
why have scientists developed artifical heart
- shortage of donor hearts
- extend patients life
