the respiratory system

What is the respiratory system

A process where our body obtains oxygen and gets rid of carbon dioxide

What is internal respiration

It’s inside the cells where oxygen is delivered to blood to produce energy through a process called phosphorylation

Details of internal respiration

It’s the exchange of gases between systematic capillaries and body tissue

Oxygen moves out of blood where there is a high pressure into high pressure tissues where its partial pressure is lower so oxygen is delivered to cells for energy production

Carbon dioxide moves from tissues into blood and removed for elimination

In simple terms of internal respiration

Oxygen moves from blood- tissues

High pressure- low pressure

Carbon dioxide moves from tissues into blood to return to lungs for external respiration

What is external respiration

It’s between body and environment

Involves exchange of oxygen and carbon dioxide between atmosphere and tissues

Process of external respiration

Oxygen from air enters lungs and diffuses into blood and carries to tissues

Carbon dioxide is produced by cells and transported back to lungs and exhaled

More detail of external respiration

Oxygen moves from alveloli where pressure is high to blood where pressure is low

Carbon dioxide moves from blood to alveloli

What is pulmonary circulation

Deoxygenated blood is pumped on right hand side to the lungs by picking up oxygen and releasing carbon dioxide

What is systemic circulation

Oxygenated blood from left side of pumped throughout body and delivers oxygen to tissues

What is double circulation

It maximises efficiency of gas exchange so tissues receive oxygen they need and carbon dioxide is removed

Oxygen rich blood goes to tissues and oxygen poor blood goes to lungs at the same time

What is the upper respiratory tract

Includes all structures conducted from external environment to lower respiratory tract

Nose and nasal cavity- filters warm and humidifies air

Pharynx- passageway for air and food is divided into nasopharnx oropharynx and laryngopharynx

Larynx- contains vocal cords and protects airway with epiglottis

Functions of upper respiratory tract

Condition air

Protect lower airways

Provide an environment for speech

What is the lower respiratory tract

Begins with trachea- windpipe that contains ciliated epithelium and mucas to trap particles

Bronchi- left and right primary bronchi and divided into secondary (lobar) and tertiary (segmental) bronchi

Bronchioles- lack cartilage and leads to terminal bronchioles

Alveoli- air sacks where gas exchange happens

Functions of lower respiratory tract

Conduct air to alveoli

Remove debri through mucas clearance

Provide a site for external respiration

What is the ciliated epithelium for

Lines inner surface of trachea

Pseudostratified

Columnar epithelium

Ciliated cells have hair like projections called cilia which moves rhythmically to transport mucas and trap particles towards towards pharynx in a process called mucocillaryescalator

What are among ciliates cells

Goblet cells which secretes mucas to trap dust

What is beneath epithelial layer

Basement membrane containing blood vessels and immune cells

What is the conducting zone

Includes all features from upper and lower respiratory tract

Conducts air in respiratory zone where gas exchange happens

What is the respiratory zone

Where gas exhange actually happens

Respiratory bronchioles- have some avelioli budding on walls

Alveolar ducts- connects respiratory bronchioles to alveolar sacs

Alveolar sacs- clusters of alveoli at end of alveolar ducts

Alveoli- primary site for gas change

What happens with oxygen in respiratory zone

It diffuses from alveoli into blood in pulmonary capillaries while carbon dioxide is moves from blood into alveoli

What is the respiratory membrane for

To allow gases to be changed between alveolar air and blood in pulmonary capillaries

features of respiratory membrane

Very thin to allow rapid diffusion of oxygen into blood and carbon dioxide out into alveoli (0.5 micrometers)

What is the thorax

The sealed cavity that protects lungs, heart and other thoracic organs to allow movement of necessary breathing

What’s the rib cage

Protects organs and provides attachment for muscles

What’s the sternum

Central anterior bone of chest

What’s the thoracic vertebrae

Provides posterior support

What are the key muscles in thoracic cavity

External intercostals- between ribs and elevates ribs during respiration

Internal intercostals- between ribs and assisting in experation by depressing ribs

Diaphragm- dome shaped muscle separating thoracic from abdomen and main muscle for breathing and contraction

What does inspiration do to volume of oxygen

Increasing volume as thorax expands due to muscles that allow for expansion of cavity

What’s the primary muscle for inspiration

The diaphragm as the diaphragm flattens done increasing verticals dimentions of thoracic cavity allowing air to flow into lungs

External intercostal muscles elevate ribs to expand thoracic cavity

Scalene muscles- elevate first and second rib

Pectoralis minor- helps raise ribs when arms are fixed

What is quiet expiration

Occurs during normal resting exhalation and doesn’t require much muscluar effort

Driven by elastic recoil and is a passive process

What is forced exploration

Active process during rapid movement like coughing

Uses muscles to decrease thoracic volume

Ribs are depressed and abdominal muscles compress pushing diaphragm up

Decreased thoracic volume increases pulmonary pressure expelling air from lungs

Components of respiratory mechanism

Air enters trachea and conducted through bronchi into lungs

Alveoli is where gas exchange happens

The oxygen enters blood and carbon dioxide leaves the lungs

Lungs are elastic allowing them to recoil during exhalation

What is surrounding the lung

Visceral pleura which is a thin membrane that covers each long

What is the pariteral pleura

It lines thoracic cavity and diaphragm

What is the interplural space

Contains fluid that helps lungs slide smoothly during breathjng

What does it mean when diaphragm flattens

It enlarges thoracic cavity creating negative pressure so air can come in

What is the pleural sac

Double layered membrane surrounding each lung reducing friction and facilitating lung movement

Sac contains negative pressure to keep lungs expanded

What happens to movement of chest wall

It changes in pressure to inflate and deflate lungs

What happens to pressure in quiet inspiration

Chest wall moves outwards

Interplueral pressure falls from -2 to. -8

IPP exerts suction on vicereal pluera and stretches lungs

Alveolar pressure in below atmosphere pressure so air can move down pressure gradient into lungs

What happens to pressure in quiet expiration

Chest wall moves inwards

Pressure rises from -8 to -2

IPP exerts suction on lungs so it recoils

Alveoli are compressed and pressure increases above atmospheric pressure

What is collapsed lung

Due to a loss of interplueral pressure due to entry of air (pneumothorax) blood (haemothrox) or lymph (chylothorax)

Lung is no longer stretched and collapses due to small volume

How can lung volume be measured

By a spirometry to see how much air is inhales and exhaled as well as how quickly you can blow air out

Spirometers record what

Volume and flow of air

What is tidal volume

The air inhaled or exhaled during a normal breath -500ml

What is inspiratory volume

The additional air you inhale after a normal breath

What is expiratory reserve volume

The addition air you exhale after normal expiration

What is residual volume

The air that remains in the lungs after the maximal exhalation

How do we work out inspiratory volume

It’s tidal volume + inspiratory reserve volume

How to work out residual volume

Expiratory reserve volume and residual volume

How to work out the vital capacity

The vital capacity is total If you can move in combining IVR, TV and EVR

How to work out total lung capacity

Combine TV, ERV, IRV and RV

What is breathing rate

Number of breaths per min

What is respiratory minute volume

The volume of air entering or leaving lungs per min

How to work out respiratory volume

RV= TVx BR

Why does not all air we breath reach alveoli

Some air stays in conducting zone called dead space as it dosent participate in oxygen or carbon dioxide exchange it humidities and filters air

How to work out air reaching alveoli

TV- dead space

How to work out alveolar ventilation the volume of air entering lungs that will actually each alveoli to participate in gas exchange per min

AV= (TV-dead space) x respiratory rate- breaths per min

Which breathing is more efficient for tidal volume

Slow deep breathing