respiration Flashcards
(32 cards)
what’s Internal Respiration
-Within the cell, CO2 produced – Glycolysis Krebs Cycle
-O2 consumed – Oxidative Phosphorylation.
-end stages of respiration
whats External Respiration
-Ventilation
-Exchange and transport of gases around the body
-how we get gas from air to cells
overview of respiratory system
-respiratory and cardiovascular system work together with transportation
-diffusion of gases out if the lungs into capillaries
-heart pumping oxygen around body
-haemoglobin carries O2
-lost of CO2 carried back as carbonate
what are the two sections of the lungs branches
-conducting zone- provide pathways to get air to and from respiratory zone- no gas exchange taking place
-respiratory zone- where gas exchange takes place
whats the Conducting Zone
-Nose
-Nasopharynx
-(Mouth) Oropharynx
-Pharynx
-Larynx
-Trachea
-Bronchial Tree
-as you breathe in you filter air using structures inside nose using nasal hair- large particles are filtered
what air is gas more soluble in
-cold
whats the Structure of Bronchial Wall
-Reinforced with cartilage
-smooth muscle
-mucous glands
-elastic tissue
-bronchi help structure from not collapsing
what does The Respiratory Epithelium consist of
-Ciliated epithelia
-Goblet cells - secrete mucous
-Sensory Nerve Endings - pick up chemicals e.g. smoke
what do the bronchioles consist of
-Lack cartilage support
-Lined by respiratory epithelium
-Proportionately more smooth muscle
-more prone to collapsing as less cartilage
what do the alveoli consist of
-large SA
-Fed from terminal bronchiole
-Thin walled
-where gas exchange takes place
-very thin cells- epithelia
-optimised for gas exchange
whats The Air Blood Barrier
-A ‘sandwich’ created by flattened cytoplasm of type I pnemuocyte and the capillary wall
-For gas exchange to take place multiple barriers have to be crossed
-Large surface area for gas exchange (50-100m2
-alveoli surrounded by a network of capillaries
-air needs to pass 5 biological membranes- am, bm, 2 capillary , then alveoli membrane
what are the two processes of ventilation
-Inspiration
-Expiration
-Both of these processes can be quiet (at rest) or forced (when active e.g. during exercise).
-Importantly the movement of air occurs down pressure gradients.
-During inspiration: Patmos > Palv so air moves into the lungs
-During expiration: Palv>Patmos so air moves out of the lungs
whats Quiet inspiration
-Quiet inspiration involves the primary muscles of inspiration
-The diaphragm and The external intercostals
-Effect – increase thoracic and lung volume
-Air movement follows principles of Boyle’s Law. The increase in volume, leads to a reduction in pressure. Air moves into the lungs down the pressure gradient
-intercostal muscle lie between ribs and hence can lift the ribcage up and down
whats forced inspiration
-As well as the primary muscles, Accessory (or Secondary) muscles of inspiration are used.
-Scalenes- in your neck to the top of your ribs- helps pull ribcage up when exercising
-Sternocleidomastoids
-Neck and back Muscles
-Upper respiratory tract muscles.
whats quiet expiration
-Quiet expiration is a passive process using elastic recoil
-There are no primary muscles of expiration.
-Relaxation of external intercostal muscles
-Recoil of the lungs (elastic forces returning lungs to original size)
-Diaphragm relaxes
whats forced expiration
-Accessory muscles
-Internal intercostals
-Abdominal muscles- forced diaphragm back up
-Neck and back muscles
whats the pleura
-Pleural cavity filled with secretions
-Prevents lungs from sticking to the chest wall
-Enables free expansion and collapse of lungs
what happens during At rest elastic forces in lungs and chest balance
-Elastic nature of lungs would tend to cause them to collapse inwards
-The chest wall would tend to expand.
-At rest these inward and outward forces balance – as a result the pressure in the intrapleural space is less than atmospheric pressure.
compliance equation
c= change in V/ change in P
what does low compliance mean
more work required to inspire
what does high compliance mean
-often also involves more difficulty expiring (loss of elastic recoil)
Components of Elastic Recoil in the Lung
-Two major components to the Elastic Recoil of the Lungs.
-‘Anatomical’ component – elastic nature of cells and extracellular matrix.
-Elastic recoil due to surface tension generated at air-fluid interface
whats surface tension
-Due to difference in the forces on water molecules at the air/water interface a surface tension develops.
-In a gas bubble there is a balance between the pressure exerted by the gas and the surface tension at the gas/water border.
-Relationship described by Laplace’s equation
P=2T r -In the lung, many air sacs of different volumes. Because of Laplace’s equation, the pressure in the larger sacs is lower than smaller sacs. Air will flow from smaller alveoli to larger, leading to their collapse.
whats surfactant
-The problem of smaller alveoli collapsing is overcome by the production of surfactant.
-Surfactant produced by Type II pneumocytes. It is composed of a number of lipids and proteins
