Respiratory System Essay

Submitted By PetitLapin89
Words: 4111
Pages: 17

The Respiratory System

Topic 1: The Lung

* Efficient exchange: distance between air and blood must be small (0.5um) and surface area for exchange must be large (100m2)

LO 1: Internal, external and cellular respiration

External respiration: oxygen absorbed from the atmosphere into the blood within the pulmonary capillaries, and carbon dioxide is secreted

Internal (or tissue) respiration: exchange of gases between blood in systemic capillaries and the tissue fluid and cells that surround them

Cellular respiration: individual cells gain energy by breaking down glucose (and alike molecules) – the mitochondria consume oxygen and generate carbon dioxide

Pulmonary ventilation: (breathing) the bulk movement of air into lungs and out of lungs. Ventilation pump = rub cage + intercostal muscles + diaphragm
External Respiratory
Internal Respiratory
Cellular Respiration
Ventilatory pump
External Respiratory
Internal Respiratory
Cellular Respiration
Ventilatory pump

LO 2: Nasal cavities and their function

Nasal cavity * Tall and narrow * Vibrissa – dense hair, first defence for large particles * Lined with ciliated mucous membrane humidifies and warms inspired air * Medial surface is flat * Lateral surface has 3 sloping shelves (middle and superior conchae – turbinate muscles) that surface area of mucous membrane – turbinate bones between conchae creates turbulance within cavity * Paranasal sinuses (air-filled) open into cavity – lighten the face and add resonance to voice * Cavity roof lined with olfactory eputhelium – sniffing creates turbulance that brings air up to epithelium – axons of olfactory receptors lead toward brain through peforations in overlying bone (the cribriform plate)
LO 3: Three regions of the pharynx and the oesophagus

* Pharynx: vertical passage with 3 parts – each has anterior opening 1. Nasopharynx – connects to nasal cavity air conducting tube (upper most part of throat) 2. Oropharynx - where food enters 3. Laryngopharynx - * Pharynx is an airway and food-way – primary part of the gastrointestinal system

* Soft palate closes the Nasopharynx e.g. during swallowing to prevent food entering nasal cavity

Sleep apnea: An elongated and enlarged soft palate impinges on the posterior airway at the level of the nasopharynx and oral pharynx.
Sleep apnea: An elongated and enlarged soft palate impinges on the posterior airway at the level of the nasopharynx and oral pharynx.

LO 4: Trachea

* The windpipe: 12cm long tube – thick as your thumb * C-shaped cartilage rings = support (maintain open passage) and protection * Free ends of cartilage rings connect by trachealis muscle (smooth) – contraction narrows trachea diameter (debated functional significance) * Ciliated epithelial lining (pesudostratified columnar) – transport mucous sheet upwards to nasopharynx (mucociliary escalator) * Oesophagus is immediately posterior to trachea – in groove of trachealis muscle

- Trachealis muscle contracts during cough reflex to help expel object

- Mucociliary escalator – during a cold become over congested by mucous cilia don’t beat well together

LO 5: Descending order of size of the conducting and respiratory airways

Conducting part: series of cavities and thick-walled tubes that conduct air between the nose and deepest recesses of the lungs – in doing so warm, humidify and clean it * Nasal cavities, pharynx, larynx, trachea, bronchi and bronchioles

Respiratory part: tiny, thin-walled airways where gases exchange between air and blood * Respiratory bronchioles, alveolar ducts and sacs and the alveoli themselves

Conducting Zone | Structure:TracheaMain stem bronchi (primary)Lobar bronchi (secondary Segmental bronchi (tertiary)Smaller bronchiBronchiolesTerminal bronchi | Generation:01234-910-1516-19 | | Respiratory Zone | Respiratory bronchiolesAlveolar ductsAlveolar sacs