Respiratory physiology. External respiration. Functional organisation of the airways, lungs and thoracic cage. Mechanics of breathing. Intrapleural and intrathoracic pressure. The effect of surfactant. Protective reflexes – cough and sneeze. Two lungs, consist of tiny air-containing sacs ca

resp physiology

Two lungs, consist of tiny air-containing sacs called alveoli- bronchioles- pathway for air

The alveoli are the sites of gas exchange with the blood.- about 300million in lung

The airways are the tubes that air flows through from the external environment to the alveoli and back.

• Responsible for gas exchange: oxygen intake and carbon dioxide removal

• Includes nose and nasal cavity: filters and warms air

• Pharynx : air + FOOD passageways + RESONATING CHAMBER FOR SPEECH SOUNDS

• LARYNX - VOICE BOX

• Trachea: directs air to lungs, supported by c shaped cartilage, divides into L and R bronchi

• Bronchi and bronchioles: branch into lungs

• Alveoli: tiny air sacs where gas exchange occurs

The thoracic cage is a bony and cartilaginous structure that encloses and protects the lungs, heart, and other organs in the chest.

• Supports cellular respiration by supplying oxygen for energy production

Inspiration is the movement of air from the external environment through the airways to the alveoli during breathing.

• Expiration is movement in the opposite direction. An inspiration and expiration constitute a respiratory cycle.

• Respiration is the process whereby oxygen and carbon dioxide diffuse in and out of the blood. Respiration is

known as gas exchange, occurs in two areas of the body.

• External respiration refers to gas exchange across the respiratory membrane in the lungs between alveoli and

venous blood (deoxygenated blood).

• As venous blood flows through the pulmonary capillaries,

• oxygen diffuses into the blood and carbon dioxide diffuses into the alveolar gas.

• Each gas diffuses down its own partial pressure gradient - that is, from a high to low partial pressure.

EEXTRA

• Respiration is a physical process by which an organism takes in oxygen from the surrounding medium and release carbon dioxide.

  External respiration is the gas exchange between the lungs and the blood; however, the internal respiration is the gas exchange between the blood and the cells

• LUNG IS COVERED BY VICERSAL AND PARIETAL PLEURA, BETWEEN THERE IS A PLEURAL CAVITY

• LEFT LUNG = 2 LOBES, RIGHT = 3

• UPPER RESP PART: NOSE,ORAL CAV, PHARYNX

• LOWER: TRACHEA, BRONCHI, BRONCHIOLES, ALVOELI

mechanics of breathing

inter plural and i trattoria if pressure

INTRAPLEURAL / INTRATHORACIC PRESSURE

• pressure in the pleural cavity - usually the pressure is slightly less than the atmospheric pressure

• if the pleural cavity is ruptured the intrapleural pressure becomes equal or exceeds the atmospheric pressure -> pneumothorax

• pressure depends on the ventilation phase, atmospheric pressure, and the volume of the intrapleural cavity VAV like vavavavoom

surfactant

Pulmonary surfacant

A fluid made up of a mixture of phospholipids, proteins and calcium ions

Secreted by the alveolocyte type 2 cells and helps to reduce tension at the surface of the lungs. makes it easier for the lungs to stretch.

A deep breath causes more surfactant to be secreted due to the stretching of the alveolcyte type 2 cells. Functions of surfactant

• Increases lung SA and lung compliance

• Prevents collapsing of small alveoli

• Reduces fluid filtration- to prevent swelling

cough and sneeze

Cough reflex

• body rids the lower respiratory tract of any irritant that enters through the air

• or any fluids and solids that may spill into the respiratory tract.

• The lower respiratory tract (trachea, bronchi and bronchioles) is lined with epithelium that contains sensory

receptors -pulmonary irritant receptors./ c fibres

• Inflammation and mucus hypersecretion can trigger coughing.

• triggered by any irritation of the upper respiratory tract

Sneezing

• Sneezing is body’s way of removing irritants from the nose.

• A sneeze is an involuntary and powerful expulsion of air.