Chapter 3: Transport in animals Flashcards
In 11 steps, outline the order into how ventilation in a fish happens
- Mouth opens
- Buccal cavity floor lowered
- this increase the volume + decreases the pressure of buccal cavity
- Water enters mouth down a pressure gradient
- Opercular cavity expands
- Buccal cavity floor raised
- Pressure inside buccal cavity = higher than opercular cavity
- Water moves from buccal cavity into opercular cavity
- Mouth closes and operculum opens
- Sides of opercular cavity move inwards, increasing pressure
- Water rushes out of fish through operculum
What is the function of the operculum?
To cover the gills - helps force water over gills surface
What’s the importance of folded lamellae?
Large surface area = short diffusion path
How does the counter current mechanism ensure that the maximum amount of oxygen passes into the blood?
Large SA of the lamellae - allows the blood and water to flow in opposite direction so gas exchange can occur over the entire surface
Describe inspiration (include the intercostal muscles and diaphragm)
External intercostal muscles contract - pulling ribcage upward and outward
Diaphragm contracts
Volume of thorax and lungs increases, reduced pressure and air moves down the pressure gradient
Compare relaxed expiration (RE) and forced expiration (FE)
In both, the internal intercostal muscles contract
In FE, abdominal muscles contract pushing diaphragm upwards while in RE, the diaphragm relaxes
Describe the function of cartilage
Rigid and flexible to prevent collapsing
Is smooth muscle found in the bronchioles and bronchus?
YES
Purpose of smooth muscle?
Constricts bronchioles and controls airflow
What do elastic fibres do?
Recoil if stretched
What’s the function of goblet cells?
To produce mucus to trap debris to be wafted by cilia
What do ciliated epithelium cells do?
Waft mucus
What’s the equation for the ventilation rate?
Tidal volume x breathing rate
Which factors affect the rate of diffusion across membranes?
Surface area to volume ratio and the thickness of the membrane
What’s the difference between an open and closed circulatory system?
Open - blood goes from the heart into a body cavity
Closed - blood travels from the heart in blood vessels
Define single circulation
Blood goes from the heart to the respiratory surface and then to the body
What’s the difference between partial double circulation and double circulation?
Double circulation - separate circulation to the respiratory surface and to the body
Partial - blood from a single ventricle enters a forked aorta for distribution to the body and gas exchange surface
Give an example of the type of organism that has a single, double and double partial circulation
Single - fish
Double - Mammals
Double partial - Amphibians
Define haemolymph
Blood in an insect
Why is single circulation inefficient?
Loss of pressure when blood goes through capillaries - oxygen and nutrients delivered at a slower rate - lower level of energy
Why does being cold blooded mean that demand for O2 and nutrients will be lower?
Lower metabolic demand than a warm blooded animal
Don’t have to maintain body heat - lower respiration rate
Describe the circulation of blood in the pulmonary circulation
Under lower pressure than systemic
Blood pumped to lungs for oxygenation
Right atrium and right ventricle
Pulmonary artery and pulmonary vein
Describe the circulation of blood in the systemic circulation
Blood pumped to body tissues
High pressure - oxygen delivery quick
Why is there a separate pulmonary and systemic circulation?
To keep oxygenated and deoxygenated blood separate and different pressures
Describe the structure of an artery and their functions
Thick outer layer - collagen fibres: Protects blood vessel
Thick inner layer of muscle - elastin: Allows muscle to expand to maintain high pressure
Endothelium: Controls vascular relaxation and contraction
Narrow central lumen: Helps maintain high blood pressure
What’s the key function of an artery?
To take blood away from the heart at a high pressure and redistribute oxygenated blood around the body
Describe the function of capillaries
Remove waste products from blood
White blood cells can squeeze through the cell wall - tissue fluid
Describe the structure of capillaries
Walls = 1 cell thick
narrow lumen = single file blood cells
Describe the structure of veins
Thin outer layer
Endothelium
large lumen - low pressure
Describe the function of veins
Carries deoxygenated blood towards heart
Give two examples of plasma proteins
Albumin
Fibrinogen
Define Oncotic pressure
The pressure exerted by the proteins in the blood plasma
How does oncotic pressure work?
It draws tissue fluid back into capillaries by osmosis and vice versa - As the blood reaches the end of the capillary bed, the pressure in the capillary is lower than at the start, meaning that the oncotic pressure is higher so it draws out tissue fluid by osmosis
What is the role of tissue fluid?
To transport oxygen and nutrients from the blood to the cells and carry CO2 back into the blood
Define hydrostatic pressure
4.6 kPa - the pressure of the capillary
What is ‘lymph’
Tissue fluid that has been drained into the lymph system
Why would lipid concentration be high in the lymph draining the small intestine?
The villi absorb the lipid into the lymphatic system
Why does the pressure in the heart rise at the first 0.1 second into a heartbeat?
The atrium contracts, increasing the pressure as it pushes blood into the left ventricle
Cardiac muscle is myogenic, what does this mean?
It contracts within the tissue rhythmically
Where is the bicuspid valve located?
Left side of the heart between atria and ventricle - two flaps
Describe the tricuspid valve and where it’s located
Right side of the heart between atria and ventricle - three flaps
Define systole and diastole
Systole: contraction of the muscle
Diastole: relaxation
What is the sino-atrial-node also known as?
The pacemaker of the heart
