W5 Respiratory Flashcards
State and describe 5 functions of the respiratory system
- Olfaction/ smelling
- Phonation /speaking, vocal cords
- Cleaning warming and humidification of inspired air: dust paricals stick to nasal mucosa
- Conduction of air: series of airways allowing airflow to reach the alveoli from the nose or mouth
- Gas exchange: exchanges of CO2 and O2 between the alveoli and the pulmonary capillaries
Name and describe the (13) anatomy of the principal organs of the upper respiratory tract
Upper respiratory tract: nose.
Nasal bone
Maxilla
Palatine bone
Septum separates the nasal cavity into L and R..
Nasal conchae are 3 folds of tissue on the lateral wall of each fossa.
Meatuses: 3 passageways includes mucosa: consists of olfactory nerve cells and rich lymphatic plexus.
Paranasal sinuses: 4 pairs of sinuses lined with respiratory mucosa
Nasopharynx ciliated pseudostratified columnar epithelium, receives auditory tubes.
Oropharynx: stratified squamous epithelium
Larngopharynx: stratified squamous epithelium
Epiglottis: flap of cartilaginous tissue that guards glottis, directs food and drink to esphagus.
Glottis: vocal cords
Larynx: Intrinsic and extrinsic mucles ; open and close the glottis, forms part of the ariway to the lungs and protects.
Name and describe the anatomy of the principal organs of the lower respiratory tract
Trachea: Composition Epithelial layer + submucosa
Lungs: 3 x Lobular in shape separated by fissures, consists of alveolar tissue, bronchioles, bronchi, blood vessel and elastic lung tissue.
Bronchial tree:
Primary bronchi
Secondary bronchi
Tertiary bronchi
Bronchioles
Respiratory bronchioles
Alveolar ducts and sacs
Alveoli -
- Type 1 cells; 95% of surface area, sit of gas diffusion
- Type 2 cells; 5% of surface area, functions alveolar epithelial repair and surfactant secretion
- Alveolar macrophage; phagocytosis of particles , bacterial and loose RBCs.
Two layers of serous membrane Visceral (on ribs) and parietal (lines rib cage), lubricated with fluid
Relate 3 examples of how the structural features of the respiratory system reflect its function
- Epithelial tissue in the presence of olfactory mucosa in the upp nasal cavity traps odorants so that the cells can detect them, therefore protect w mucosa from external environment.
- The vocal cords are suspended between thyroid and artenoid cartilages production of different sounds.
- A smooth sided nasal cavity mean air in the center of cavity passes without touching the sides.
Name the muscles of respiration and describe their roles in breathing
Breathing (pulmonary ventilation) flow of air creates a pressure difference between air pressure within the ling and atmospheric pressure.
- Diaphram is responsible for pulmonary respiration. Inspiration: diaphram contracts, ↑ thracic volume. Expiration: diaphram relxation returns the muscle to a dome shape ↓ thoracic volume.
- Skeletal muscles are responsible for lung sizr changes to create flow.
Inspiration: requires recruitment of skeltal muscle to create a pressure gradient and drive flow.
Expiration is oassing using elastic recoil of lung tissue and rib cage.
Forced inspiration:
- Scalenes
- Sternocledomastoid
- Pectoralis minor
- external intercostals
Forced Expiration:
- Internal intercostals
- Rectis abdominal
- Internal and external oblique muscles
Explain how pressure gradients account for flow in and out of the lungs, and explain how these pressure gradients are produced
Boyle’s Law: at a constant temperature, pressure inversely proportional to volume.
Charle’s Law: at a given pressure, the volume of a quantity of gas is directly proportional to it’s temp. Air moves ↓ gradient. From ↑ to ↓
Explain how pressure gradients account for flow in and out of the lungs, and explain how these pressure gradients are produced
Boyle’s Law: at a constant temperature, pressure inversely proportional to volume.
Charle’s Law: at a given pressure, the volume of a quantity of gas is directly proportional to it’s temp.
Air moves ↓ gradient. From ↑ to ↓.
Inspiration: VRG cause diaphram and external intercostals contraction ↑ volume of the thorax. ↓ in intrapulmonary pressure.
Intrapulmonary pressure is 3mmHg ↓ than atmospheric pressure therefor airflows from the atmosphere into lungs.
Epiration: Diaphram relaxs elastic recoil takes over . ↓ in thorasic volume = ↑ in intrapulmonary pressure.
Intrapulmonary pressure is 4mmHg higher than atmospheric pressure. Air flows from the lungs into the atmosphere.
Forced expiration: VRG recruits the accessory respiratory muscle, causes intra pulmonary pressure to ↑ to as much as +30mm Hh.
- Interal intercostal muscles depress the ribs
- Contraction of abdominal muscles ↑ intra-abdominal pressure forces upwards ↑ pressure in thorasic cavity
State the sources of resistance to pulmonary airflow and discuss their relevance to respiration
- Pulmonary compliance - How easy the lungs expand - Opposite of elasticity
- Bronchiole diameter - primary control over resistance to airflow bronchoconstriction - triggered by airborne irritants, cold air PNS, histamine. Bronchodilation - SNS nerves, adrenaline.
- Alveolar surface tension - Thick film of water needed for gas exchange. Pulmonary surfactant (detergent) which prevents alveolar collapse during expiration, produced by type II alveolar cells
Define anatomical dead space and relate this space to alveolar ventilation
Not all inspired air reached the alveoli or undergoes gas exchange.
Anatomical dead space: Air tha tremains in the conducting zone that does not undergo gas exchange
Alveolar dead space: Air that reached the alveoli but does not undergo gas exchange (pathological)
Define clinical measurements of pulmonary volume and capacity
Tidal volume: breathing in and out at rest, in one breath
Residual Volume (RV): air remaining in lungs after maximum expiration, this air keeps the alveoli open and cannot be breathed out.
Minute respiratory volume (MRV): V x respiratory rate. maximum voluntary ventilation.
Vital capacity (VC): total amount of air that can be exhaled with effort after maximum inspiration.
Total lung capacity (TLV):maximum amount of air the lungs can hold. Measured with a spirometry.
Explain why matching ventilation and perfusion is important for efficient gas exchange in the lungs.
Alveolar ventilation: airflow to the alveoli.
Alveolar perfusion: blood flow to the alveoli
Effciency of gas exchange can be maintained by limited ability to match perfusion to ventilation
State the diagnostic tests used for obstructive and restrictive lung disorders and state typical results found for each
Measuring Ventilation (spirometry)
FVC - Forced Vital Capacity; Amount of air expired in a forced expiration after maximal inspiration
FEV - Forced Expiratory Volume in one second: amount of air expired in the first second of a forced expiration
FEV/FVS % - 80% PEF
Peak Expiratory Flow : maximun speed of exhalation
Discuss the regulation of ventilation, including the homeostasis of blood gases and pH, and the primary factors that influence the respiratory control centre and thereby control respirations.
Breathing requires stimulation from the brain for Skeletal muscle contraction Centralised control of multifple muscles.
Voluntary control - Frontal lobe to the respiratory neurons in spinal cord.; Alters blood concerntrations of CO2 and O2.
Involuntary control from medulla olongata and Pons
- Dorsal respiratory group (DRG)
- Ventral respiratory group (VRG)
- Central chemoreceptors: reacts to changes in the pH of cerebrospinal fluid.
- Peripheral chemoreceptors: ↑ breathing rates by responds to concerntration of CO2 O2 and pH in blood.
- Irritant receptors: reacts to the presence of irritants Stretch receptors: responds to excessive inflation triggers to stop inspiration
- Limbic system and hypothalmus: respiratory effects of pain and emotion
Define partial pressure and discuss its relationship to a gas mixture such as air (Dalton’s Law)
Inspired air: at sea level 1 atm of pressure = 760mmHg.
Daltons law → total pressure = the sum of all the partial pressures of gas in a mixture.
Important for predicting the movement of gasses. The pressure of a specific gas in a mixture, moving down their gradient. (gas exchange between blood an alveoli
Contrast the composition of inspired and alveolar air
The difference in gas concerntrations result from:
- Humidification of the air in the respiratory tract - ↑ the P h20.
- Mixing of inspired and residual alveolar air PcO2 and ↓ in P o2
- Gas exchange ↑ on PCO2 and ↓ in P02
State the methods in which O 2 and CO 2 are transported in the blood stating values for each
Oxygen and carbon dioxide are transported as solutes and as parts of molecules of certain chemcial compounds.
Hemoglobin (Hb): made up for 4 polypeptides chains with iron contain heme group. → Carbon dioxide can bind to amino acids, and oxygen binds to iron in heme group.
Oxygen travels in 2 forms: bound to hemoglobin as oxyhemoglobin → dissolved in blood plasma. Carbon dioxide → bicarbonate ions into plasma → bound to haemoglobin carbaminohaemolglobin.
Explain what the oxygen-hemoglobin dissociation curve shows
It shows relative amount of O2 that is attached (saturated) to the hemoglobin molecule for a given partial pressure of o2.
The curve shows that as the partial pressure of o2 is ↑, HB saturation ↑.
The curve shows the o2 unloading from Hb is favoured at the systemic tissues were the Po2 is ↓ and o2 loading onto Hb ↑ saturation is favored at the alveoli due to ↑ Po2s
