The Respiratory System

Question 1

Cellular Respiration

Answer 1

Glucose + Oxygen - Carbon Dioxide + Water

Question 2

Requirements for Gas Exchange

Answer 2

•diffusion of gases works best across a moist membrane
•the more surface area, the more gas exchange
•delicate membranes must be protected
•need a constant flow of O2 across the exchange membranes
•need a way to transport gases to all cells in the organism

Question 3

Microorganisms

Answer 3

•very small (most uni-cellular)
•constant contact with their external environment
•gas exchange occurs by diffusion across their membranes

Question 4

Diffusion

Answer 4

the movement of molecules from a high concentration to a low concentration. It occurs passively - no energy required - so if there was more oxygen in one area (high concentration), the oxygen molecules would automatically move to an area with less oxygen (low concentration)

Question 5

Large Aquatic Organisms (not a big idea)

Answer 5

•moist membrane is no problem
•transport is by a circulatory system
•surface area is increased by gills
•gills are very delicate so must be protected by gill cover
•they need a fresh supply of oxygenated water so the organism either keeps moving or has moving parts

Question 6

Terrestrial Organisms

Answer 6

•secrete own moisture across the exchange membranes
•can be highly folded to increase surface area
•membranes are inside the body for protection
•highly vascularized: lots of blood flow near the membranes to exchange and transport gases
•require a mean of oxygenated air across the lung membranes: breathing

Question 7

Breathing

Answer 7

•the mechanism is based on a pressure system
•when a container increases in volume, it creates a partial vacuum so air is drawn in and when it decreases in volume, air is pushed
•external intercostals pull rib cage out when contracted, internal intercostals pull rib cage in when contracted

Question 8

Diaphragm

Answer 8

•lines the bottom of the lungs and the rib cage, lowers when contracted
•the outer surface of the lungs is connected to the inside of the chest cavity by pleural membranes when the chest cavity increases or decreases they pull these elastic membranes and the lung tissue almond with them

Question 9

Inhaling

Answer 9

•diaphragm and external intercostal muscles contract
•lungs are pulled out and down
•air pressure is reduced in the lungs
•air is drawn in

Question 10

Exhaling

Answer 10

•external intercostals and diaphragm relax
•internal intercostals contract
•lungs (due to there elasticity) regain their normal size
•air pressure is increased
•air is pushed out

Question 11

Nostrils and Nasal Cavity (1a)

Answer 11

•functions: warming, moistening, and filter air, sense of smell
•lined with mucus and cilia to trap dust particles

Question 12

Components of the Gas Exchange System

Answer 12

Nostril and Nasal Cavity and Mouth, Trachea, Bronchi and Bronchioles, and Aveoli

Question 13

Mouth (1b)

Answer 13

•greater volume of air can enter and exit, however, it is not warmed or filtered as much

Question 14

Trachea (2)

Answer 14

•the glottis is the opening between the pharynx and the upper end of the trachea
•the glottis is protected by the epiglottis during swallowing, the larynx (voice box) sit just below the glottis: inhaled air passes around it, exhaled air can pass around it or through it

Question 15

Structure of the Trachea

Answer 15

•series of C-shaped cartilage rings are imbedded in the walls (prevents collapse)
•lined with cilia and mucus: these trap and sweep out dust particles

Question 16

Bronchi and Bronchioles (3)

Answer 16

•the trachea branches into the bronchi (one to each lung)
•these branch into several bronchioles
•there structures are similar to that is the trachea (although the smallest bronchioles have no cartilage)

Question 17

Alveoli (4)

Answer 17

•each terminal bronchioles ends in a cluster of avellane sacs
•the walls of the aveoli are only one cell thick, surrounded by a dense bed of blood
•the infoldings of the aveoli provide a large surface area
•this is the site of gas exchange

Question 18

Oxygen Transport

Answer 18

•O2 dissolves poorly in water, and blood is mostly water (1.5% dissolves)
•instead (98.5%) it is carried by binding to hemoglobin molecules in red blood cells (RBC)
•hemoglobin (Hb) is a protein consisting of 4 polypeptide chains and 4 iron atoms
•about 280 million Hb molecules per RBC

Question 19

Carbon Dioxide Transport

Answer 19

•20-30% of CO2 is carried to the lungs by Hb
•5-10% dissolves in plasma (this makes blood slightly acidic)
•60-70% is transported as bicarbonate ions after CO2 reacts with water in RBC to form carbonic acid, which then dissolves
•therefore, as we exhale and release CO2 our blood becomes more basic

Question 20

Gas Exchange (Carbon Dioxide)

Answer 20

•as blood containing CO2 flows to the cooler temperature of the lungs, the CO2 diffuses out of the blood and into the aveoli
•this frees up Hb and it can now pick up oxygen gas

Question 21

Gas Exchange (Oxygen)

Answer 21

•at cooler temperatures and neutral pH, O2 binds strongly to Hb
• these conditions exist in the lungs, so O2 readily diffuses from alveoli to capillaries and into red blood cells
•at warmer temperatures and acidic pH, O2 does not bind as strongly to Hb, so it is released
•these conditions exist in body tissue, so O2 leaves blood and diffuses into surrounding cells

Question 22

Oxygen Use

Answer 22

•cells use absorbed O2 to help produce energy during cellular respiration, therefore, your level of activity determines how much O2 you use
•blood pressure is measured in millimeter of mercury (mmHg)

Question 23

VO2

Answer 23

•the rate at which oxygen is used by the body (units = mL of O2/kg of body mass/minute

Question 24

VO2max

Answer 24

•a persons maximum VO2
•can be used as a measure of respiratory health and/or fitness

Question 25

Control of Breathing

Answer 25

•breathing can be controlled consciously and unconsciously

Question 26

Conscious Control of Breathing

Answer 26

•speech, vocal training, etc

Question 27

Unconscious Control of Breathing

Answer 27

Medulla Oblongata
•chemoreceptor cells here measure pH levels
•if pH gets too low (i.e. less basic due to increased CO2), these receptors increase the frequency of nerve impulses to the breathing muscles
•increased muscle contraction - increased breathing rate

Question 28

Involuntary Breathing

Answer 28

•is controlled by the respiratory centre in the brain stem
•breathing rate and depth increase if the [CO2] in the blood increases

Question 29

Regulation of Breathing Rate

Answer 29

•breathing can be controlled by both consciously and unconsciously
•consistent control: cardio fitness, speech and vocal training
•unconscious control: respiratory centre medulla oblongata, found in the brain, due to a negative feedback cycle, in place to maintain homeostasis, various chemoreceptors detect changes in the pH of the blood

Question 30

Bronchioles

Answer 30

•chemoreceptors measuring pH can also dilate or constrict the bronchioles

Question 31

Aorta & Carotid Arteries

Answer 31

•receptors near the heart measure oxygen levels and signal the medulla to alter breathing rates
•you cannot hold your breath forever

Question 32

Sneezing and Coughing

Answer 32

•are automatic reflexes used to clear the pathway of dust and/or excess mucus

Question 33

Hyperventilation

Answer 33

•vigorous, forced ventilation (quick, shallow breathing)
•diffusion of CO2 increases out of the blood and into the aveoli, without the usual corresponding diffusion of oxygen
•this increases blood pH (more alkaline)
•even though not much oxygen is present in the blood, medulla oblongata slows down breathing rate
•person may pass out

Question 34

High Altitude

Answer 34

•lower air pressure causes changes to atmospheric gas concentration (less O2 in air)
•diffusion rate of O2 is reduced; diffusion rate of CO2 out is increased
•so, blood CO2 is reduced , blood pH increases (more alkaline)
•medulla is not stimulated

Question 35

Carbon Monoxide (CO) Poisoning

Answer 35

•carbon monoxide is chemically similar to O2
• it can bind to Hb, and doesn’t releases itself very readily
•less oxygen is transported

Question 36

Pneumonia

Answer 36

•due to infection, the body increases mucus and pus secretion in aveoli
•aveoli fill up with fluid, preventing gas exchange
•x-rays can show if lungs are blocked by fluid
•bacteria pneumonia can be treated with antibiotics
•infants and seniors are more susceptible and 5% fatality rate

Question 37

Asthma

Answer 37

•abnormal constriction of bronchioles restricts air flow
•various causes (e.g. exercise-induced, allergies, stress)
•increase mucus production making diffusion of gases more difficult

Question 38

Emphysema

Answer 38

•alveolar walls breakdown, reducing surface area for gas exchange

Question 39

Pneumothorax

Answer 39

•a collapsed lung caused by the introduction of air between the pleural membranes