respiration in human Flashcards
state the function of nostrils, nasal cavity, larynx, trachea, bronchus
nostrils: entrance to respiratory tract
nasal cavity: cleaning, moistening and warming of incoming air
-hairs on walls of nostrils filters dust and bacteria from inhaled air
-mucus secreting cells secrete mucus to trap bacteria and dust
-blood capillaries close to the surface of the cavity to warm up inhaled air
larynx: contains vocal chords
trachea: supported by C shaped rings of cartilage preventing trachea from collapsing during breathing due to the change in air pressure
bronchus: trachea divides into two tubes, bronchi. each bronchus divides into numerous fine tubes, bronchioles and each bronchiole ends in a cluster of alveoli
describe role of cilia in breathing
inner wall of the trachea known as epithelium is lined with ciliated cells and gland cells. gland cells secrete mucus to trap dust particles and bacteria. cilliated cells have hair like strucutres called cilia and it helps to sweep the dust trapped mucus up the bronchi and trachea away from the lungs into the pharynx where they can be swallowed or expelled.
role of diaphragm ribs and intercostal msucles in breathing
breathing is achieved by the change in volume of chest cavity by the movement of ribs and diaphragm.
movement of diaphragm is controlled by intercostal muscles. there are two sets of intercostal muscle, internal and external intercostal muscles. both are antagonistic.
a sheet of muscular and elastic tissue known as the diaphragm seperates the thorax from the abdomen. it contracts to expand chest cavity and relaxes to allow chest cavity to return to original volume.
state the adaptation and functions of alveoli
one cell thick: provide a shorter distance for faster rate of diffusion of oxygen into the blood
each alveolus is covered with a film of moisture: enable oxygen to dissolve to increase its rate of diffusion into the blood
each alveolus is surrounded by numerous blood capillaries: blood capillaries transport diffused oxygen away from lungs and carbon dioxide from bloodstream to the lungs for removal.
continuous transport of gases maintains the concentration gradient of the gases for a faster rate of diffusion
alveoli are present in large quantities: provide a large surface area to volume ration to increase rate of diffusion of gases
what happens when you inhale
diaphragm contracts and flattens. internal intercostal muscle relaxes while external intercostal muscle contracts. lungs expand and when volume of lung increases, air pressure decreases. ribcage moves upwards and outwards. air moves from the air into the lung as it moves from a higher atmospheric pressure to lower air pressure in the lungs.
what happens when u exhale
diaphragm relaxes and curves upwards to form a dome shape.
external relaxes and internal intercostal muscle contracts. ribcage moves downwards and inwards. lungs are compressed as volume of lungs decreases, air pressure increases. air move from higher air pressure in air to lower atmospheric pressure into the atmosphere
describe how oxygen is carried in the blood
alveolar air contains a higher concentration of oxygen than the blood. oxygen dissolves in the thin film of moisture on the inner surface of the alveoli
it then diffuses through the walls of the alveoli and blood capillaries into the blood where it diffuses into the red blood cells.
oxygen binds with haemoglobin in RBC to form oxyhaemoglobin( the reaction is reversible and direction in which this takes place is dependent on the concentration of oxygen in the surroundings
when blood passes through oxygen poor tissues, the oxyhaemoglobin releases oxygen which will then diffuse through the walls of the capillaries into the body cell
properties of nicotine and its effects on the body
addictive stimulant drug that causes the release of adrenaline makes blood clot easily. increases heart rate and blood pressure increases risk of blood clots in the arteries if blood clots in the arteries this will result in coronary heart disease.
