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Flashcards in W5 Respiratory Deck (24)
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1

State and describe 5 functions of the respiratory system

1. Olfaction/ smelling

2. Phonation /speaking, vocal cords

3. Cleaning warming and humidification of inspired air: dust paricals stick to nasal mucosa

4. Conduction of air: series of airways allowing airflow to reach the alveoli from the nose or mouth

5. Gas exchange: exchanges of CO2 and O2 between the alveoli and the pulmonary capillaries

2

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.

3

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

4

Relate 3 examples of how the structural features of the respiratory system reflect its function

1. 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.

2. The vocal cords are suspended between thyroid and artenoid cartilages production of different sounds.

3. A smooth sided nasal cavity mean air in the center of cavity passes without touching the sides.

5

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.

1. Diaphram is responsible for pulmonary respiration. Inspiration: diaphram contracts, ↑ thracic volume. Expiration: diaphram relxation returns the muscle to a dome shape ↓ thoracic volume.

2. 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

6

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 ↓

7

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

8

State the sources of resistance to pulmonary airflow and discuss their relevance to respiration

1. Pulmonary compliance - How easy the lungs expand - Opposite of elasticity

2. Bronchiole diameter - primary control over resistance to airflow bronchoconstriction - triggered by airborne irritants, cold air PNS, histamine. Bronchodilation - SNS nerves, adrenaline.

3. 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

9

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)

10

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.

11

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

12

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

13

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

14

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

15

Contrast the composition of inspired and alveolar air

The difference in gas concerntrations result from:

1. Humidification of the air in the respiratory tract - ↑ the P h20.

2. Mixing of inspired and residual alveolar air PcO2 and ↓ in P o2

3. Gas exchange ↑ on PCO2 and ↓ in P02

16

Define Henry’s Law and discuss how this law affects the gas exchange of O 2 and CO 2 at the lungs

Partial pressure difference for gas exchange between air in lungs and blood in capillaries,.

Gases dissolve into the fluid and diffuse down their concerntration gradients.

Amount of gas that dissolves in water is determined by its solubility in water and it's partial pressure in the air. (Molecular weight and solubility of gases). 02 has a ↑ partial pressure gradient, CO2 has ↑ solubility

17

Name and describe 5 factors that govern gas exchange between the lungs and pulmonary capillaries

1. As blood enters pulmonary capillary, oxygen diffuses down it's pressure gradient. → blood.

2. Oxygen continues diffusing into blood until equilibration occurs (leaves capillary)

3. As blood enters a pulmonary capilalary carbon dioxide diffuses down it;s pressure gradient.

4. As with oxygen, carbon dioxide continues diffusing as long as their is a pressure gradient.

18

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.

19

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

20

Describe how O 2 and CO 2 loading and unloading takes place at the tissues and the alveoli

1. Exchange of gases in tissues takes place between arterial blood flowing through tissue capillaries and cells.

2. Dissolved oxygen diffuses out of arterial blood, the P02 which accelerates oxyhemoglobin dissociation to release more oxygen to plasma for diffusion to cells.

3. Carbon dioxide exchange between tissues and blood takes place in the opposite direction from oxygen exchange.

Co2 loading → Co2 unloading → O2 unloading - during exercise → CO2 unloading → O2 loading

21

8. State and describe 4 factors that alter the oxyhemoglobin dissociation curve

1. Partial pressure of oxygen (PO2). Po2 is ↓ favours release of O2 to the hemoglobin molecule.

2. Temperature: elevated tissue temp promotes o2 unloading.

3. The Bohr effect ↑ of CO2 and H+ and ↓ in pH of the systemic capillaries ↓ the affinity of O2 for hemoglobin hence promoting O2 unloading at the tissues.

4. Bisphosphoglycerate (BPG) is a metabloic intermedia of glycolysis, its production and bonding to hemoglobin weakens the affinity of 02 to Hb hences prototes o2 uploading at tissues

22

Explain the physiological basis why respiration is increased at exercise onset

↑ respiration during exercise onset is caused by; ↓ commands form the motor cortex to the working muscles by ↓ commands to the respiratory center to ↑ respiration in anticipation of respiratory exercise demands.

Exercise stimulates joint and muscle proprioceptors and sends sensory signals to brain stem medulla to ↑ respiration.

23

At what rate does O2 and C02 diffuse?

At the same rate 1:1, oxygen has a much larger pressure gradient, forcing its diffusion. Carbon dioxide is more soluble driving it's diffusion

24

Name and describe 5 factors that govern gas exchange

1. Concentration gradient of gasses @ the alveoli at the tissue,

2. Solubility of gas (Henrys Law): o2 and co2 diffuse at same rate.

3. Membrane thickeness: o.5um thick. ↑ by presence of fluid.

4. Membrane surface area: 100ml blood in alveolar capillaries, ↓ in pathologies such as emphysema.

5. Ventilation-Perfusion Coupling - Blood flow should match airflow.