The respiratory system

Question 1

Smoking

Answer 1

Smoking is a threat to human life. Cilia that line the respiratory airways and normally sweep away pollutants and microbes are immobilized for hours. Smoking kills the white blood cells that defend the respiratory tract. puts body at risk for cancer, high blood pressure, and elevated levels of bad “cholesterol”

Question 2

The respiratory system functions

Answer 2

to bring oxygen into and carbon dioxide out of the body

Question 3

Airways

Answer 3

pathways for oxygen and carbon dioxide

Question 4

through Nasal Cavities of the nose..

Answer 4

air enters and leaves the respiratory system; the nasal cavities are separated by a septum of cartilage and bone

Question 5

Hair and ciliated epithelium filter..

Answer 5

dust and particles from the air

Question 6

Blood vessels..

Answer 6

warm the air and mucous moistens it

Question 7

The paranasal sinuses

Answer 7

lie just above the cavities and are linked to them by channels

Question 8

route air moves

Answer 8

nasal cavities—>pharynx—->larynx—–>vocal chords( the gap between the chords in the glottis)—->trachea—–>bronchi(one bronchus goes to each lung). The trachea leads from the larynx downward to branch into 2 bronchi, which are lined with cilia and mucous to trap bacteria and particles. The vocal chords at the entrance of the larynx vibrate when air passes through the glottis, allowing us to make sounds; during swallowing, the glottis closes to prevent choking.

Question 9

Lungs

Answer 9

are elastic and provide a large surface area for gas exchange. Human lungs are housed in the rib cage above the diaphragm; the two lungs are separated by the heart. Each lung is enclosed by a pair of thin membranes called pleurae; the pleural membrane is folded in a matter that forms a pleural sac leaving an intrapleural space filled with intrapleural fluid. Bronchi narrow inside the lungs to form bronchioles ending in respiratory bronchioles. Tiny clustered sacs called alveoli bulge out from the walls of the respiratory bronchioles. Together the alveoli provide a big surface area for gas exchange with the blood located in the dense capillary network surrounding each alveolar sac

Question 10

Respiration

Answer 10

the overall exchange of inhaled oxygen from the outside air for exhaled carbon dioxide waste. This exchange happens in the alveoli after this the cardiovascular system is in charge of moving gasses in the body.

Question 11

Respiratory systems rely on..

Answer 11

the diffusion of gasses down pressure gradients. Air is Nitrogen=78% oxygen=21% Carbon=0.04% and other gasses=0.96%

Question 12

Partial pressures..

Answer 12

can be calculated for example oxygen is 160mm Hg. Oxygen and Carbon Dioxide diffuse down pressure gradients from areas of high partial to low partial pressure. Gasses enter and leave the body by diffusing across thin moist respiratory surfaces of epithelium, the speed and extent of diffusion depends on the surface area present and on the partial pressure gradient.

Question 13

When hemoglobin binds..

Answer 13

with oxygen it helps maintain the pressure gradient. Hemoglobin is the main transport protein. Each protein binds 4 molecules of oxygen in the lungs (high oxygen concentration) and releases them in tissues where oxygen is low by carrying oxygen away from the lungs the gradient is maintained.

Question 14

Gas exchange rules change when …

Answer 14

oxygen is scarce

Question 15

Hypoxia

Answer 15

occurs when tissues do not receive enough oxygen; at high altitudes the partial pressure of oxygen is lower than sea level so the hyperventilation may occur. Underwater divers must breathe pressurized air from tanks and avoid nitrogen narcosis, where nitrogen dissolves into the body including the brain; divers must also ascend to the surface slowly to prevent nitrogen bubbles in the blood–the “bends” or decompression sickness.

Question 16

The respiratory cycle

Answer 16

the continuous in/out ventilation of the lungs and has two phases: Inspiration and Expiration

Question 17

Inspiration(inhalation)

Answer 17

draws breath into the airways

Question 18

Expiration(exhalation)

Answer 18

moves breath out of the airways

Question 19

During the respiratory cycle

Answer 19

volume of the chest cavity increases then decreases and the pressure gradients between lungs and outside air reverse. this works b/c the air in the air ways is the same pressure as the outside atmosphere. Pressure in the alveoli (intrapulmonary pressure) is also the same as the outside air.

Question 20

The basic respiratory cycle

Answer 20

To inhale the diaphragm contracts and flattens, muscles lift the rib cage upward and outward, the chest cavity volume increases internal pressure decreases, air rushes in. To exhale the actions listed above are reversed; the elastic lung tissue recoils passively and air flows out of the lungs.

Question 21

Active exhalation

Answer 21

involves contraction of the abdominal muscles to push the diaphragm upward forcing more air out

Question 22

The lungs are…

Answer 22

stretched to fill the thoracic cavity by a slight diff. between the intrapulmonary pressure(higher) and the intraplueral pressure(lower). In a collapsed lung (pneumothorax) , air enters the pleural cavity, disrupting the normal expansion and contraction of the lungs.

Question 23

How much air is in a breath

Answer 23

About 500ml of air (tidal volume) enters and leaves the lungs with each breath. A human can forcibly inhale 3,100 ml of air (inspiratory reverse volume) and forcibly exhale 1,200 ml (expiratory reverse volume).

Question 24

Vital capacity

Answer 24

The max volume that can be moved in and out is called the vital capacity (4,800 ml for males, 3,800ml for females

Question 25

A Residual volume

Answer 25

of about 1,200 ml remains in the lungs and cannot be forced out

Question 26

Heimlich manuever

Answer 26

sometimes food enters the trachea and not the esophagus it can be forced out through here which forces the diaphragm to elevate pushing air into the trachea to dislodge the obstruction

Question 27

Ventilation

Answer 27

moves gasses in and out of the lungs; its different from respiration which is the actual exchange if gasses between the blood and cells.

Question 28

External Respiration

Answer 28

oxygen moves from the alveoli to the blood; carbon dioxide moves in the opposite direction

Question 29

Internal respiration

Answer 29

oxygen moves from the blood into tissues and vice versa for carbon dioxide

Question 30

Alveoli’s are masters for gas exchange

Answer 30

Each alveolus is only a single layer of epithelial cells surrounded by a thin basement membrane and a net of lung capillaries, also with thin basement membranes. Between the 2 basement membranes is a film of fluid. Together the systems form the respiratory membrane. The partial pressure gradients are sufficient to move oxygen in carbon dioxide out of the blood passively.

Question 31

Pulmonary surfactant

Answer 31

is a secretion produced by the alveoli that reduces the surface tension of the film to prevent collapse of the alveoli; infant respiratory distress syndrome occurs in premature babies who lack the ability to make the surfactant.

Question 32

Hemoglobin is the oxygen carrier

Answer 32

Blood cannot carry sufficient oxygen and carbon dioxide in dissolved form as the body requires; hemoglobin helps enhance its capacity to carry gasses by transporting oxygen

Question 33

path that oxygen diffuses down a pressure gradient

Answer 33

blood plasma—->red blood cells—–>hemoglobin where it binds at a ratio of 4 oxygen to one hemoglobin to form oxyhemoglobin. Hemoglobin gives up its oxygen in tissues where partial pressure of oxygen is low; blood is warmer , and ph is lower, all 3 conditions occur in tissues with high metabolism. When tissues are chronically low in oxygen , red blood cells produce DPG(2,3-siphosphoglycerate), which decreases the affinity of hemoglobin for oxygen, allowing more oxygen to be released to the tissues.

Question 34

Hemoglobin and blood plasma…

Answer 34

carry co2 because carbon dioxide concnetration is higher in body tissues than in blood it diffuses into the blood capillaries. 7% stays dissolved in plasma. 23% binds with hemoglobin( forming carbonohemoglobin) and 70% is a bicarbonate form. Bicarbonate and carbonic acid formation is enhanced by carbonic anhydrase, an enzyme located in red blood cells. Reactions that make bicarbonate are reversed in the alveoli where the partial pressure of CO2 is low.

Question 35

Respiratory pace maker

Answer 35

controls the rhythm of breathing. Automatic mechanisms ensure a regular cycle of ventilation. Clustered nerve cells in the medulla coordinate the signals for the timing of exhalation and inhalation; the pons fine tunes the rhythmic contractions. The nerve cells are linked to the diaphragm muscles and the muscles that move the rib cage; during inhalation, nerve signals travel from the brain to the muscles causing them to contract and allowing the lungs to expand.

Question 36

Normal exhalation

Answer 36

follows relaxation of muscles and elastic recoil of lungs. When breathing is deep and rapid , stretch receptors in the air way send signals to the brain control centers, which respond by inhibiting contraction of the diaphragm and rib muscles forcing you to exhale.

Question 37

CO2 is the trigger …

Answer 37

The nervous system is more sensitive to levels of carbon dioxide and uses this gas to regulate the rate and depth of breathing.

Question 38

Sensory receptors in the..

Answer 38

in the medulla detect hydrogen ions produced when dissolved co2 leaves the blood and enters the cerebral spinal fluid bathing the medulla. The drop in ph in the cerebral spinal fluid triggers more rapid and deeper breathing to reduce the levels of co2 in the blood.

Question 39

changes in levels of…

Answer 39

carbon dioxide, oxygen, and blood ph are also detected by carotid bodies, located near the carotid arteries, and aortic bodies located near the aorta; both receptor signal increases in ventilation rate to deliver more oxygen to tissues.

Question 40

Chemical controls in alveoli match air flow to blood flow

Answer 40

when the rate of blood flow in the lungs is faster than the air flow; the bronchioles dilate to enhance the air flow and thus the rate of diffusion of the gasses. When the air flow is too great relative to the blood flow, oxygen levels rise in the lungs and cause the blood vessels to dilate, increasing blood flow.

Question 41

Apnea

Answer 41

a brief interruption in the respiratory cycle; breathing stops and then returns normally

Question 42

Sleep Apnea

Answer 42

is a common problem of aging b/c the mechanism for sensing changing oxygen and carbon dioxide levels gradually become less effective over the years

Question 43

Tabaco is a major threat and smoking ..

Answer 43

has both immediate and long term effects (for example loss of cilia function) and long term effects such as lung cancer. One cigarette can harm you and the ones around you through second hand smoke.

Question 44

Pneumonia

Answer 44

occurs when the inflammation in lung tissues and the buildup of fluids makes breathing difficult; pneumonia can sometimes occur when infections that start in the nose and throat, like influenza, spread.

Question 45

Tuberculosis

Answer 45

arises from infection by the bacterium

Question 46

Myobacterium Tuberculosis

Answer 46

the diseases destroy patches of lung tissue and can cause death if untreated

Question 47

Histoplasmosis

Answer 47

caused by fungus; treatment is possible, but the infection can sometimes spread to the eyes, causing impairment or blindness

Question 48

Bronchitis

Answer 48

caused by air pollution, cigarette smoke, or infection, leads to increased mucus secretions, interference with ciliary action, and eventual inflammation and possible scarring of bronchial walls. If bronchitis continues so most of the bronchi become scarred and blocked with mucus , emphysema occurs

Question 49

Emphysema

Answer 49

alveoli start to break down, further eroding the ability to breathe

Question 50

Asthma

Answer 50

occurs in response to numerous allergens; smooth muscles in the bronchiole walls contracts in spasms, mucus rushes in, and breathing becomes difficult. Steroid inhalers may be needed to relieve some symptoms.