Exchange Surfaces in Animals Key Terms and Processes Flashcards
Why do multi cellular organisms need specialised transport systems?
- the metabolic demands of most multi cellular organisms are high, and diffusion distances will be too long in far too inefficient to provide and supply quantities needed
- the surface area to volume ratio gets smaller as the organism gets larger, so along with diffusion distance, surface area available to absorb or remove substances becomes relatively smaller
- molecules such as hormones or enzymes may be secreted in one place, but is needed in another
Open Circulatory Systems
The transport medium is pumped straight from the heart into the body cavity of the animal (haemocoel)
Closed Circulatory Systems
The blood is enclosed in blood vessels and does not come directly into contact with the cells of the body, the blood is pumped under pressure around the whole boy.
Tissues of the circulatory system (state where they are present and their function)
- Cartilage
- Found in trachea
- C-shaped cartilage rings provide structural support, prevents trachea from collapsing in on itself, keeps airways open
Tissues of the circulatory system (state where they are present and their function)
- Goblet cells
- Found inside the trachea, bronchi, and larger bronchioles in the respiratory tract
- They secrete mucus so particles/pathogens can be trapped, it reduces the chance of lung infection
Tissues of the circulatory system (state where they are present and their function)
- Ciliated Epithelial Cells
- Found in the trachea
- Wafts mucus to the back of the throat where it can be swallowed and destroyed by stomach acid or coughed out
Tissues of the circulatory system (state where they are present and their function)
- Smooth Muscle
- Found in the walls of bronchi and bronchioles
- When the smooth muscle contracts, the lumen of the airway reduces, and dilates so the lumen is wider
Tissues of the circulatory system (state where they are present and their function)
- Elastic Tissue
- Found in airways and alveoli
- The elastic tissue allows the airway to recoil to its original shape after the smooth muscle has contracted; the elastic fibers also allow the expansion of the alveoli, without bursting. It also allows them to recoil after exhalation
Tissues of the circulatory system (state where they are present and their function)
- Capillaries
- Found around airways and alveoli
- glucose, amino acids and water are all provided by capillaries to cells in the airways, and they allow O2 and CO2 to be transferred
Tissues of the circulatory system (state where they are present and their function)
- Squamous Epithelial Cells
- Found in the alveoli in the lungs
- Used for absorption and diffusion
Inhalation
- Diaphragm muscle contracts and flattens due to nervous impulse from the medulla oblongata along the phrenic nerve, pushing the digestive organs down
- The external intercostal muscles between the ribs contract due to nervous impulses from the medulla oblongata along the thoracic nerves and causes the ribs to rise up and out, the internal intercostal muscles relax
- The volume of the thoracic cavity increases
The pressure in the thoracic cavity decreases below atmospheric pressure - Air moves from the high pressure atmosphere, through the nasal passages, down the trachea to the lungs and into the alveoli where there is a lower pressure
Exhalation
- The diaphragm muscle relaxes and rises up due to pressure from the digestive organs
- The external intercostal muscles between the ribs relax and cause the ribs to fall
- The volume is the thoracic cavity decreases
- The pressure in the lungs increase to above atmospheric pressure
- The air in the alveoli moves out, up the bronchi, trachea and out through the nose or mouth
Tidal Volume
The volume of air moving in and out of the lungs at rest
Respiratory Reserve Volume
Volume of extra air you can breathe in during forced inspiration above tidal volume
Expiratory Reserve Volume
Amount of extra air you can breath out during forced expiration
