Exchange Of Substances Flashcards
What is diffusion
The random movement of molecules from a region of high concentration to a low concentration until dynamic equilibrium is reached
Passive process
What is osmosis
The random movement of water across a partially permeable membrane from a less concentrated solution to a more concentrated solution
High to low water potential
What is facilitated diffusion
High to low concentration
Passive process (requires no ATP)
Through a carrier protein
What is co transport
- Sodium ions are actively transported out of the epithelial cells into the blood via the sodium-potassium pump
- Sodium ions diffuse into the cell from lumen using sodium-glucose co-transported proteins
- Glucose is therefore also transported into the cell
- Glucose passes into the blood plasma via facilitated diffusion
What happens during inhalation
Internal intercostal muscles relax External intercostal muscles contract Ribs move up and out An increase in volume The diaphragm flattens and contracts Pressure lowers
What happens during expiration
Internal intercostal muscles contract External intercostal muscles relax Ribs move down and in Decease in volume The diaphragm relaxes and becomes domed Pressure higher
Features of a lung
Trachea Bronchus Ribs External intercostal muscles Internal intercostal muscles Diaphragm Bronchioles Alveoli Lungs
Role of alveoli
LSA:volume
Very thin- short diffusion pathway
Partially permeable- allows selected material to pass
Movement of internal/external medium- maintains diffusion gradient
Pulmonary fibrosis
Scars form on epithelium cells- thickened
Longer diffusion pathway
Elasticity reduced
Shortness of breath Dry cough Pain in chest Weakness Fatigue
Asthma
Allergens (eg. Dust, fur, pollen) Lining of airways inflamed Cells secrete mucus Fluid enters airways Muscles surrounding bronchus contract
Difficulty in breathing
Wheezing
Coughing
Emphysema
Due to smoking
Elastin permanently stretched=scarring
Alveoli has a smaller surface area and bursts
Shortness of breath
Coughing
Bluish skin
Tuberculosis
Caused by mycobacterium tuberculosis
Grows in upper regions of the lungs
White blood cells at the side of infection= inflammation and increases size of lymph nodes
Coughing (up blood)
Fever
Fatigue
Loss of appetite
How do you find out pulmonary ventilation?
Pulmonary ventilation= tidal volume (dm^3) x ventilation rate (min^-1)
How does oxygen move from an alveolus to the blood
Via diffusion (lower con in blood stream and higher in alveolus) High diffusion gradient as blood is constantly moving Through epithelium which is thin(1 cell thick) means a short diffusion pathway
How to increase the rate of diffusion
Increase the con. Gradient
Increase the size of exchange surface
Decrease thickness of Exchange surface
Increase the movement of internal/external medium
