Respiratory System Flashcards
what are the the major components of the human respiratory system?
1) Nasal cavity
2) larynx
3) trachea
4) Bronchial Tree
5) Alveoli
what is the function and location of the nasal cavity?
Function:
- Providing an airway for respiration
- Moistening and warming the entering air
- Filtering inspired air
Location: back of nostril
what is the function and location of the larynx?
Function: seperation of food and air way, voicebox
Location: above trachea
where is the trachea located?
belown larynx and above bronchi
what are the parts of the bronchial tree and where are they located?
1) left/right primary bronchus
2) left/right secondary bronchus
3) tertiary bronchi
4) bronchioles
5) terminal bronchioles
6) respiratory bronchioles
what is below the bronchial tree?
alveolar ducts
alveolar sacs composed of alveoli
how much alveoli do we have and what does it contain?
approx. 300 million
has extensive network of capillaries
what is the structure of an alveoli?
thin walls so o2 and co2 can change places
epithelial cells
flattened shape
some have macrophages
what is the mechanism of ventilation (breathing)?
the process of getting o2 rich air into the lungs and co2 out of the lungs
where are lungs located?
in the thoracic cavity
surrounded by the ribs and seperated from the abdomen by the diaphragm
what are the 2 membranes that the lungs are surrounded by?
the pleural membranes
what consists of the pleural membranes?
1) parietal pleura
2) visceral pleura
seperated by a fluid filled cavity = pleural cavity
what are the functions of the fluid in the pleural cavity?
1) lubrication
2) holds the 2 membranes together
what does forced exhalation involve?
relaxation/ contraction of internal intercostal and abdominal muscles
what happens to the chest, lungs and diaphragm with inhalation?
chest = increase volume
lungs = decreases pressure
diaphragm = contracts & moves downward
what happens to the chest, lungs and diaphragm with exhalation?
chest = decrease of volume
Lungs= increase of pressure
diaphragm = relaxes and moves up
what are the sequence of events for inspiration?
1) inspiratory muscles contract (diaphragm lowers)
rib cage lifts up and out
2) thoracic cavity volume increases
3) lunges streches, intrapulmonary volume increases
4) intrapulmonary pressure drops
5) air flows into lungs down its pressure gradient
what is the sequence of events for expiration?
1) inspiratory muscles relax (diaphragm rises)
rib cage down and back
2) thoracic cavity volume decreases
3) elastic lungs recoil passively
intrapulmonary voume decreases
4) intrapulmonary pressure rises
5) air flows out of lungs down its pressure gradient
what is breathing regualted by?
the breathing control centres
where are the breathing control crentres located?
pons and medulla region in brain
what is the medulla function (inspiratory centre) for breathing?
- normal inspiration
- sends impulses to inspiratory muscles every few seconds
what is the function of the medulla for the expiratory centre?
- only active during exercise
- activated by inspiratory area
- stimulates expiratory muscles to cause forceful exhalation
what is active/inactive in the inspiratory area with normal breathing?
Active:
2 seconds
diaphragm ad external intercostals contract
normal quiet inhalation
Inactive:
3 seconds
Diaphragm and external intercostals relax
normal quiet exhalation
what happens during forceful breathing?
inspiratory area active:
diaphragm, sternocleidomastoid, and scalene contract
forceful inhalation
expiratory area:
internal intercostal and abdominal muscles contract
forceful exhalation
what are the 2 areas of pons?
1) pneumotaxic ares
2) apneustic area
what is the function of the pneumotaxic area of pons?
- sends inhibitory impulses to the inspiratory area to shorten inspiratory period
prevents lungs from overfilling
AKA shortens length of breath
what is the function of the apneustic area of pons?
- send inhibitory impulses to the inspiratory area to lengthen the inspiratory period
- occurs when oxygen levels are lower than normal (high altitude)
AKA lengthens breath
what is the hering-breuer reflex?
prevents lungs from over-inflating
how does the hering-breuer reflex work?
- stimulates stretch lining in lining of lungs which signals to the brain
- the signals inhibit both inspiratory area and apneustic area
- inspiration stops
what is the function of chemoreceptors?
constantly measure O2 and CO2 concentrations
where are central chemoreceptors located?
medulla oblongata
where are peripheral chemoreceptors located?
aortic bodies
carotid bodies
how is maintenance of normal o2 and co2 levels contained?
negative feedback
what is the negative feedback loop for cemical changes disrupting homeostasis?
Stimulus: increase of aterial blood PCO2
Receptor: central chemoreceptors in medulla + peripheral chemoreceptors in aortic/cartoid bodies sends nerve impulses
Control centre: inspiratory area in medulla oblongata sends nerve impulses
Effector: muscles of inhalation and exhalation contact more forcefully/more frequently (hyperventilation)
Response: decrease in arterial blood PCO2, increase in pH and PO2
what is a spinogram?
a chart that shows how much air is taken in
what is the tidal volume in a spirogram?
the volume breathed in/out while at rest
approx. 500 ml
what is the expiratory reserve volume in a spirogram?
the max volume of air that can be forced out after normal exhalation
1000 ml
what is inspiratory reserve volume in a spirogram?
the max volume of air that can be inhaled after a normal inhalation
3000 ml
what is vital capacity?
max volume of air that can be exhaled after max inhalation
4500 ml
what is residual volume in a spirogram?
volume of air remaining in lung after max exhalation
1500 ml
what is the total lung capicity in a spirogram?
total volume of air the lungs are capable of holding
6000 ml
what is dead air space in spirogram?
air that never enters the aveoli but remains in air passageways (stays in ducts)
150 ml
how does oxygen get into the blood?
co2 and o2 goes through capillaries
diffuses into alveolus through concentration gradient
how is all of the oxygen carried into blood?
haemoglobin (iron containing protein in RBD)
what is oxyhemoglobin?
when oxygen binds to hemoglobin
how does oxygen get from the blood to the cell & how does CO2 get from the cell to the lungs?
1) o2 enters blood through diffusion (98.5%)
2) oxygen is transported as oxyhemoglobin to capillaries
3) the oxygen from capillaries is released from haemoglobin due to acidity of co2 and enters tissue cells by diffusion
4) approx. 23% of co2 is combined with globin part of hemoglobin through diffusion
5) approx. 7% of co2 is dissolved in plasma
6) approx 70% of co2 attracts with h2o to form bicarbonate (GOES TO LUNGS)
7) co2 leaves blood by diffusion
what are the precentages of o2 transported by hemoglobin?
98.5%
what is the percentage of o2 dissolved in plasma?
1.5%
what is the percentage of CO2 transported by hemoglobin?
23%
what is the percentage of CO2 dissolved in plasma?
7%
what is the percentage of CO2 that transports as bicarbonate?
70%
what are the 5 respiratory patterns?
1) eupnoea
2) dyspnoea
3) tachypnoea
4) hyperpnoea
5) apnoea
what is eupnoea?
normal breathing
what is dyspnoea?
difficult breathing
what is tachypnoea?
fast breathing
ex: anxiety
what is hyperpnoea?
deep breathing
ex: high altitudes
what is apnoea?
lack of breathing
ex: drugs, trauma
what is hyperventalation?
increased rate and/or depth of breathing
what are respiratory and non-respiratory causes of hyperventilation?
respiratory:
asthma
non-respiratory:
exercise
fever
what are the consequences of hyperventilation?
hypocapnia
blown out all og CO2 which causes o2 to not bind off = no o2 to the brain
what is hypoxia?
reduced oxygen supply to body tissues
what are internal/ enternal causes of hypoxia?
internal:
functional deficit in body system
ex: lung problems, heart problems, or circulatory system
external:
low oxygen levels in the environment
ex: high altitudes
what are the physiological consequences of hypoxia?
cyanosis
tachycardia
dizziness
what is cyanosis?
bluish skin colour due to an accumulation of non-oxygenated blood
what is tachycardia?
increase in heart rate
what is the cause od dizzyness?
insufficient oxygen supply to the brain
