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Flashcards in Unit 1: Exchange and Transport Deck (104)
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How to increase rates of diffusion?

Thin cell wall=short diffusion distance
Large Surface area= increased rate of diffusion
Good blood supply= substances quickly removed, maintains steep diffusion gradient


Roles of cartilage?

Cartilage=supports trachea, prevents airway from collapsing in low pressure+doesn't go all the way round to allow flexibility


What is Ventilation rate?

volume of air breathed per minute

Calculated as tidal volume x breathing rate


Define Tidal volume?

Volume of air you breathe in or out during one breath


Define breathing rate?

number of breaths per minute


Define vital capacity?

total volume of air that can be expired (exhaled) after a max. inhilation


How does a Spirometer work?

Spirometer= a chamber filled with medical grade oxygen that floats on a tank of water

Attached is a disposable mouthpiece connected to the chamber which the person breathes in/out of.

Inhilation removes Oxygen from chamber so chamber sinks down

Exhilation pushes air into chamber so chamber floats up

Movement of chamber recorded by datalogger which plots trace on a graph


Define Inspiritory and Expiritory reserve volume?

Inspiritory= the extra air breathed in on top of the tidal volume

Expiritory= the extra air breathed out after a normal breath


What is the Pleural membrane?

Membranes surrounding the lungs and lining the thoracic cavity-contain a fluid that reduces friction


Define squamous epithelium cells?

The type of epithelium making up the walls of the alveolus


What happens in the diastole phase of the cardiac cycle?

=Filling phase
-relaxed atria and ventricles
-Semi-lunar valves closed
-Atrio-ventricular valves open so blood from vena cava and pulmonary vein fill atria and ventricles


What happens in the atrial systole phase of the cardiac cycle?

=Atria contracting (starts heartbeat)

-Atria volume decreases so pressure increases and blood is pushed into Ventricles
-As blood enters ventricles, Ventricles contract and blood fills atrio-ventricular valves. This forces AV valve flaps shut preventing backflow of blood


What happens in the ventricular systole phase of the cardiac cycle?

=All 4 valves start off shut

-Contraction starts at base of ventricle and pushes blood towards arteries and out of heart
-Semi-lunar valves prevent backflow into ventricle as they relax


The cardiac cycle is myogenic. Define myogenic?

Myogenic means the cardiac cyle initiates its own cycle and will beat even if the nerves attached to it stopped working


Describe how the heart coordinates itself?

Sinoatrial node (SAN) initiates a wave of excitation (electrical impulse) which spreads over atria via membranes of muscle tissue=contractions

Wave can only travel through Atrio-ventricular node (AVN). At the base of the atria there are discs of non-conducting tissue which can't conduct the impulse, creating a delay between Atria and ventricles contracting (prevents them contracting at once)

Wave travels through specialized conducting tissue (Purkyne tissue) to Apex and up walls so blood is forced upwards.


Myocardial infarction?

heart muscles respire w/ fatty acids instead of glucose. If there's a blood clot in coronary artery this deprives heart of oxygen and those cells die.


What products are taken in/removed by our transport system?

Constant supply of Oxygen, Nutrients, Amino acids and fatty acids
Rapid removal of Carbon dioxide


What kind of circulatory system do mammels have?

Closed systems-blood is always contained within a vessel


Insects have an open circulatory system. How do they ensure blood circulation?

Muscular pumping organ similar to heart. Long muscular tube under dorsal surface of the insect.
Blood enters the heart through pored (ostia) which gets pumped towards the head by Peristalsis where the blood simply pours into the blood cavity.


Circulatory system of a fish?

Closed system- Blood always in vessels
Heart can pump it at high pressure so blood flows quickly. Nutrients delivered and carbon dioxide removed quicker.


Formation of tissue fluid

When the arterial end of the capillary contracts, HYDROSTATIC PRESSURE causes the blood fluid plasma (containing dissolved nutrients and oxygen) to be pushed out of the capillaries through tiny gaps in capillary wall.
RBC,WBC, platelets and plasma proteins too big to fit through.
Tissue fluid is formed and surrounds the body cells so gas and nutrient exchange can occur.


Return of fluid back to circulatory system

Tissue fluid mostly returns to capillary through osmatic pressure (some goes into lymphatic system)

Tissue fluid and blood contain solutes giving them a -ve water potential
-Water potential of fluid is less negative so can diffuse down a concentration gradient via diffusion.


Functions of Lymphatic system

Absorption of excess fluid and its return to the blood in the chest cavity

Absorption of fat from the small intestine.

Immune system function-fluid contains immune cells which help fight infection.


What are Lymph nodes and what do they do?

Lymph nodes=places where WBC develop and lymphocytes are produced
Lymph nodes filter bacteria from blood


Properties of airways?

Large enough to supply sufficient air without obstruction
Divide into smaller airways
Stretch and recoil


Role of cartilage?

Supports trachea and bronchi under low pressure (during inhalation)
Doesn't go all round so allowing flexibility+allows oesophagus to expand when swallowing


Role of smooth muscle?

Contract to constrict airways and narrow lumen
-controls the flow of air

Isn't voluntary, can be triggered by allergic reaction to substances in airways


Role of elastic fibres?

Counteract constriction of smooth muscle-deform then reform into original shape during constriction
=allows airways to DILATE


Role of goblet cells and glandular tissue?

Produce mucus which helps trap tiny particles from the air e.g. Pollen and bacteria
=reduces risk of infection


Role of ciliated epithelium?

Have tiny, hair-like structures projecting from membrane called CILLIA

Cillia move in synchronised pattern to waft mucus up the airway, to the back of the throat. The mucus then gets swallowed and broken down in stomach killing any bacteria