The Physiology of Respiration

PathophysiologyBMS 243The Respiratory System Introduction

Dr. Aya M. Serry2015/2016

The Human Respiratory SystemThe Respiratory System is what controls breathing. It brings in the oxygen to your body, and gets rid of the carbon dioxide that is left over. If you dont breathe, you would dieWhen the human body breathes air, it gets sucked through the nostrils or the mouth. Then it goes through the trachea The trachea divides into tubes called bronchi which carry the air on to each lung The Human Respiratory System3The respiratory system consists of a series of tubes that transfer air from outside the body to the small air sacs (the alveoli ) in the lungs where gas exchange take place

The Human Respiratory SystemAt the end of the smallest bronchioles are the alveoliThere are millions of alveoli in each lungAlveoli are surrounded by a network of small blood vessels called capillaries

The Alveoli The Human Respiratory SystemAlveoli and adjacent capillariesterminal bronchiolealveolicapillaries The Human Respiratory SystemWhy do we need to breathe? Breathing gets oxygen into the body so that cells can make energy Cells use this energy to contract muscles and power the thousands of biochemical reactions that take place in the cell every second Without oxygen, cells cant make energy and without energy, cells would die The supply of blood and oxygen to cells and tissues is called PERFUSION

Physiology of RespirationInside the cells most energy is made by the mitochondria. This energy is in the form of ATP *

In the process of energy production Oxygen is consumed by the cells Carbon dioxide is produced as a waste gas Energy production*Adenosine Triphosphate Glucose fuels the processPhysiology of Respiration

Physiology of Respiration Oxygen (O2) from the air in the lungs diffuses into the bloodThen It is transported through the Blood to the cells Then, Oxygen diffuses from the blood into the cells

How do cells get their oxygen?Physiology of Respiration Carbon dioxide (CO2) from the cells diffuses into the blood Then It is transported through the blood to the lungs Then, In the lungs carbon dioxide diffuses into the air and is breathed outHow do cells get rid of their carbon dioxide?Physiology of Respiration

Exchange of O2 and CO2 between lungs and cellsPhysiology of RespirationOxygen diffuses from the alveoli to the blood in the capillariesWhile Carbon dioxide diffuses from the blood in the capillaries to the alveoliGas exchange in the alveoliPhysiology of Respiration

Gas exchange in the alveoli Diffusion is a process that occurs when there is a difference in the concentration of a substance between two areas The substance, for example oxygen, will diffuse from an area of high concentration to an area of low concentrationNo energy is required from the body for this processWhat is diffusion?Physiology of Respiration

What is diffusion?It is the changes in pressure that cause air to enter and leave the lungsBreathing air in and out of the lungs As the ribs rise and fall and the diaphragm domes and flattens, the volume and pressure in the lungs changes

Ventilation (breathing)Physiology of RespirationInhalation is the process of taking air into the lungs. For this to occur, the air pressure inside the lungs must be lower than that of the external atmosphere as air flows from areas of higher pressure to lower pressure.

This is achieved by the contraction of the external intercostal muscles which acts to pull the ribcage upwards and outwards, hence, increasing the volume of the thoracic cavity.

The diaphragm also contracts to extend the cavity further downwards.

InhalationThe size of the lungs: is increased which, in turn, creates an area of lower air pressure inside the lungs; hence, air is drawn into the lungs.InhalationExhalation is the process of expelling air out of the lungs.

For this to occur, the air pressure inside the lungs must be higher than that of the external atmosphere as air flows from areas of higher pressure to ones of lower pressure.

This is achieved by the relaxation of the external intercostal muscles which bring the rib cage inwards.

ExhalationThis, decreasing the volume of the thoracic cavity and that of the lungs which, in turn, creates high pressure in the lungs; hence air is pushed out of lungs.

ExhalationVentilation (breathing)

Inspiration (breathing in)Ribs rise and diaphragm flattensVolume increases and pressure decreasesAir enters the lungsExpiration (breathing out)Ribs fall and diaphragm domesVolume decreases and pressure increasesAir leaves the lungs

Ventilation (breathing)Physiology of RespirationAs we exercise, the body needs to obtain more oxygen and remove more carbon dioxide (CO2)This is done by increasing the rate and depth of breathingAn increase in carbon dioxide in the blood is the main trigger that increases the rate and depth of breathing HOW??Control of VentilationPhysiology of RespirationChemoreceptors in the respiratory centre in the brain stem detect an increase in blood CO2 levelsThe intercostal and phrenic nerves increase the rate and depth of breathingAdditional chemoreceptors on arteries near the heart monitor oxygen and Carbon dioxide levelsControl of VentilationPhysiology of Respiration

THANK YOU..