Download Respiratory System and Motor System Notes 2011 1

Nelson Pages 280 – 309
Biology 20 Unit D: Respiratory and Motor Systems
 Earth’s atmosphere is about:

78 % N2

21 % O2

1 % remaining gases
 Aerobic organisms require O2 for cellular
respiration
 Breathing (ventilation).
Involves movement of air between external environment and
body
 Uptake of O2 and release of CO2 by cells occurs across respiratory
membrane.

 Describes all processes that supply O2 to cells of body.
For breakdown of glucose
 Describes processes by which CO2 is transported to lungs for
exhalation.

a.) Breathing is the process of
how air enters and exits the
lungs
b.) External respiration occurs in the
lungs
 Involves exchange of O2 and CO2
molecules between air and blood
c.) Internal
respiration occurs
within body
 Involves exchange
of O2 and CO2
molecules between
blood and tissue
fluids
d.) Cellular respiration
involves production of ATP in
body cells
Energy released is used for:
Cell processes
• Growth
• Movement
• Synthesis of new molecules
Organs involved are:

Nasal cavity and sinuses

Pharynx

Larynx

Trachea

Bronchi

Bronchioles

Alveoli

Lungs
respiratory system
Warms air (contact with blood vessels).
Moistens air with secretions of the epithelial tissue.
Cleans air by trapping debris in mucus and fine hairs.
 Forms a tube common to respiratory
and digestive systems.
 Top portion of pharynx cleans the air.
 Adenoids and tonsils help in
immunity.
 2 openings branch from pharynx
 Trachea (windpipe) and
esophagus (carries food to
stomach).
 Epiglottis is a flap like structure
Covers opening of trachea when food is being swallowed
(reflex action).
 It seals opening leading into respiratory tract.

IV. larynx (voice box)
 Composed of 2 thin sheets of
elastic ligaments called vocal
cords.
 Sounds are made when cords
vibrate as air passes by them.
• Protected by a thick band of
cartilage - Adam’s apple
Voice box
Larger voice box in males
produces a deeper sound
Inflammation
• Laryngitis may result
Lined with ciliated cells that
produce mucus.
 Mucus traps debris that escape
hair filters in nasal passage.
Wall of trachea is supported by
cartilage rings, which keep trachea
open.
 Left and right bronchi also have cartilage rings
 Bronchi branch out in the lungs to become
bronchioles which have no cartilage but
smooth muscle.
 Smooth muscle in bronchioles can decrease in
diameter.
 Any closing of the bronchioles increases
resistance of air movement.
 Wheezing sound
 Air moves from bronchioles into tiny blind –
ended sacs called alveoli (singular:
alveolus).
 Small size and great # of alveoli increase surface area greatly
 Each alveolus is surrounded by capillaries
 O2 diffuses into blood and CO2 diffuses out of blood
 Due to
concentration gradients
 During inhalation
 Alveoli are bulb – shaped
 During exhalation
 Alveoli collapse
 Membranes are prevented from sticking by a film
of lipoprotein
Film allows the alveoli to pop during inhalation
Respiratory distress syndrome
Some babies do not produce enough lipoprotein
Difficulty inhaling
May result in death
 Contained within pleural
membrane

Isolate and lubricate lungs within
thoracic cavity
 Reduces friction between lungs and
chest cavity during inhalation
Pleurisy
 Inflammation of pleural membranes
and build – up of fluids in chest cavity
 Expiration is easier but inspiration is
more difficult
 Contain alveoli and bronchioles
 Stretch from clavicle to diaphragm
Lung anatomy
 Determined by action of
muscles and size of thoracic cavity
 Atmospheric pressure remains relatively constant; pressure in chest
cavity varies
 Gases move from an area of high
Dome – shaped sheet of
muscles
 Separates chest cavity from
abdominal cavity
 Regulates pressure in chest
cavity
to low pressure
 Diaphragm is assisted by movement of ribs

Ribs are hinged to vertebral column, allowing them to move up
and down
 Bands of muscles, the external
intercostals, are found
between ribs
 A second set, internal intercostals, are not used during normal
breathing, but during exercise
 Concentration of gases
inhaled:
 78 % nitrogen, 21 % oxygen,
and 0.04 % carbon dioxide
 Composition of gases
exhaled:
 78 % nitrogen, 16 % oxygen,
and 5 % carbon dioxide
 Air enters lungs when pressure of
air outside is greater than
pressure inside lungs (pleural
pressure).
 Increase size (volume) of
chest cavity.
 Diaphragm moves down.
External intercostals
(muscles) contract (the muscles
flatten).

Due to a nerve stimulus
•
Rib cage moves up and out
 Air leaves lungs when pleural pressure inside is greater than air
pressure outside
 Diaphragm relaxes and pushes up.
 Volume of chest cavity decreases
External intercostals
(muscles) relax, i.e, become
dome shaped)
No nerve stimulation
•Rib cage moves
downward
Breathing animation showing rib cage and
diaphragm:
http://www.smm.org/heart/lungs/breathing.htm
 A hit to the solar plexus (bottom of rib cage)

Drives abdominal organs upward
Dome shape of diaphragm is exaggerated
 A large quantity of air is expelled

 A bullet or a stab wound to ribs creates a hole in pleural
cavity
 During inhalation, pressure inside chest cavity is much
less than normal
• Air flows directly through hole in chest
Treatment:
 Air must be removed so that lung can re – expand
 Diffusion of a gas occurs from an
area of high to low pressure
 Dalton’s Law of Partial Pressure

Each gas in a mixture exerts its own pressure, which is proportional to
total volume
 O2 diffuses from air (21.2 kPa) into lungs (13.3 kPa for
alveoli)
 Partial pressure of O2 depends on location

Arteries carry blood away from heart

Veins carry blood toward heart
 Capillaries connect arteries with veins
I.e., are in between arteries and veins
• Are the sites of gas exchange
 O2 diffuses into cells
 CO2 diffuses out of cells
•
Product of cellular respiration
 Largest change in partial pressure of O2 is in capillaries
 Partial pressure of CO2 is highest in tissues and venous blood
 Partial pressure of N2 remains relatively constant
 Gases must be dissolved to cross cell membrane

Alveoli have a film of moisture
 O2 moves from atmosphere to alveoli; moves
into blood and dissolves in plasma.
 O2 is not very soluble in blood
 Thus, when O2 dissolves into plasma,
hemoglobin, on a red blood cell, greatly
increases O2 – carrying capacity of the blood
a. Hemoglobin

Consists of 4 polypeptides
•
Composed of:
Heme (iron – containing)
Globin (protein component)
 Each heme group contains an iron atom
Binds to O2
 When O2 dissolves into plasma, hemoglobin forms a weak bond
with O2 molecule


Forms oxyhemoglobin
•
Other O2 molecules can dissolve in plasma
O2 carrying capacity of the blood is:
 20 mL of O2 per 100 mL of blood (70 fold increase
compared to blood without hemoglobin)
 Partial pressure in lungs = 13.3 kPa
 Partial pressure in capillaries = 5.3 kPa

Partial pressures/ diffusion
of oxygen/ carbon dioxide:
http://highered.mcgrawhill.com/sites/0072437316
/student_view0/chapter44/
animations.html#
Drop in partial pressure causes dissociation (split) of O2
from hemoglobin
•
O2 diffuses into tissues
 little O2 is released from hemoglobin until partial pressure of
O2 reaches 5.3 kPa
 Ensures most O2 remains bound to hemoglobin until it gets
to tissue capillaries
 Venous blood still carries a rich supply of O2
 70 % of hemoglobin still saturated with O2 when blood
returns to heart
Partial pressure
 CO2 is 20 X more soluble than O2
 9 % of CO2 produced by tissues is carried in plasma
 27 % of body’s CO2 combines with hemoglobin

Forms carbaminohemoglobin
 64 % of body’s CO2 combines with H2O from plasma.

Forms carbonic acid (H2CO3 (aq))
•
Enzyme, carbonic anhydrase, increases rate of
chemical reaction
CO2 + H2O H2CO3
Decreases concentration of CO2 in plasma
 Ensuring that CO2 continues to diffuse into blood
H2CO3 dissociates to bicarbonate ions and hydrogen ions
 H+ ions dislodge O2 from hemoglobin

H+ combines with hemoglobin to form reduced
hemoglobin
•
Hemoglobin acts as a buffer, thus, keeping acidity down
 Bicarbonate ions are transported to plasma
Combines with H+ to form H2O and CO2
 O2 is released from its binding site and is free to move into body
cells
•
 CO2 diffuses from blood into alveoli

Eliminated during exhalation
 During exercise:

Cellular respiration increases; Causes CO2 levels to increase
Stimulates chemical receptors in brain stem

Brain impulses are carried to muscles--- increase
breathing movements, flush CO2 from body.
 Other chemical receptors in walls of carotid
artery
detect low levels of O2 in blood.
 A nerve is stimulated
• Message sent to brain
Brain relays message to muscles that control
breathing
Chemoreceptors
Specialized nerve receptors sensitive to specific chemicals
 Two types of chemoreceptors:

1.Carbon dioxide chemoreceptors
2.Oxygen chemoreceptors
 Chemoreceptors located in medulla

oblongata of brain
Detects increased amount of CO2, in the form of an acid, in
blood
 Nerve cells in medulla oblongata send nerve impulses to
diaphragm and intercostals

Breathing rate increases and exchange of CO2 and
O2 is sped up

Once the level of CO2 decreases, chemoreceptors
then become inactive
 Sensitive to low O2 levels in blood
 Chemoreceptors are found in carotid and aortic arteries

Messages are sent to medulla oblongata
•
Message is then sent to intercostal muscles and
diaphragm to increase breathing rate
2nd function is detection of high levels of CO2 in blood
 Oxygen receptors act as a
back up system

Are only called into action when O2 levels are low and CO2
levels high

In high altitudes
Air is thinner
• Carotid and aortic chemoreceptors stimulate breathing
movement
 CO competes with O2 oxygen for active site on hemoglobin
molecule
•
 Lungs
Increased ventilation provides
additional O2 and removes excess
CO2
 Kidneys
 Remove excess H+ from blood
 Muscles
 Increased activity produces
more CO2
 CO2 and H+ increase
 Increased O2 demand of
muscles lowers O2

Adrenal gland
 Epinephrine is released in response to exercise
•
Hormone causes breathing rate to increase
 Can vary (as will the amount of gas exchanged).
 Tidal volume = amount of air exchanged at rest.
 Vital Capacity = amount of air exchanged at maximum
conditions.
A. Bronchitis
 Bacterial or viral infections
 Reactions to environmental
chemicals
•
Narrowing of air passages and
inflammation of mucus lining in
bronchial tubes
Mucous cells secrete more mucus
Tissues swell in bronchioles
As mucous secretions increase, air movement decreases

Bronchioles are not supported by bands of cartilage to
help keep them open
B. Asthma
- often associated with allergies
C. Emphysema (“over – inflated”)
 Walls of alveoli become inflamed; thin walls stretch and
rupture.
 Greater effort is required to exhale than inhale
 Uncontrolled growth of cells
Greatly decreases surface area for diffusion
 Tumors may actually block bronchioles, thereby reducing
airflow to the lungs, potentially causing the lungs to collapse

 Read Section 9.3 in your textbook




– Pages 292 – 297
Complete Section 9.3 Questions
1-3,5-6, Page 297
Smoking and Lung Cancer Case
Study – Page 295, Questions 1-6
Lung Capacity Pre-lab Questions
in Workbook
Lung Capacity Lab
 1. Carbon dioxide stimulates chemoreceptors in the medulla
oblongata, the brain centre that controls breathing.
 2. CO2 acts as a competitive inhibitor. It attaches itself to
hemoglobin, thereby limiting the transport of oxygen. Low levels
of oxygen are detected by the chemoreceptors in the carotid
artery and aortic arch. The stimulated chemoreceptors send
nerve messages to the medulla, which, in turn, sends nerve
messages to the diaphragm and rib muscles to increase
breathing movement.
 3. Inflammation of the bronchioles reduces airflow from the
lungs. As pressure builds up in the lungs, alveoli begin to rupture.
This reduces the surface area available for gas exchange in the
lung.
 4. Gases diffuse from an area of high partial pressure to an area of
lower partial pressure. Oxygen diffuses from air (partial pressure
of 21 kPa) into the lungs (partial pressure of 13.3 kPa).
 5. Approximately 9 % of the CO2 dissolves in plasma, 27 %
combines with hemoglobin to form carbaminohemoglobin, and
64 % combines with water from the plasma to form carbonic acid
(H2CO3).
 6. CO2 combines with water to form carbonic acid. Being
unstable, the carbonic acid dissociates into HCO and H+ ions. The
carbonic acid must be buffered. The hydrogen ions dislodge
oxygen from hemoglobin and then combine with the hemoglobin
to form reduced hemoglobin. By removing the hydrogen ions
from solution, hemoglobin serves as a buffer.
Biology 20 – Chapter 9 Notes
Human body has  600 muscles
3 types of muscles
 Muscle of the heart
 Involuntary
 Makes heart
beat
 Controlled by nerves of autonomic nervous system
 Is striated

Narrow stripes or bands that are visible under a
microscope
Involuntary
 Found in the lining of many organs
Stomach, esophagus, uterus, walls of blood vessels
 Unstriated

Voluntary
 Makes the bones of skeleton move

Walk, talk
 Are attached to tendons

Band of connective tissue that joins muscle to bone
 Many skeletal muscles are arranged in pairs

Work against each other to make a joint move
• Antagonistic
muscles
 When biceps contract, triceps relax

Bones forming elbow joint are
brought closer together
 When biceps relax, triceps contract

Two bones move apart
Flexor

Muscle that contracts to bend a joint (Bicep).
Extensor

Muscle that contracts to straighten a joint (Tricep)
Joints http://www.brainpop.com/h
ealth/skeletalsystem/joints
“Origin”

Place where the muscle attaches to a stationary bone
“Insertion”

Place where muscle attaches to moving bone
 Ensures that biceps and triceps do not attempt to pull against each
other
• Excitatory nerve impulses cause triceps to contract
• Inhibitory nerve impulses cause biceps to relax
I.) Skeletal Muscle
 Enables movement, smiling, and keeping body
warm
 80 % of energy used in skeletal muscle contraction is lost as heat
 Composed of several bundles of
cells called fibres
Fibres
Most cells contain only 1 nucleus
 However, many nuclei are found
in each muscle cell
 Enclosed within a membrane

•
Sarcolemma
 Within muscle fibres are tiny
myofilaments bundled together
 Two types of myofilaments
1. Actin – thin filaments
2. Myosin – thick filaments
 Each myofilament is composed of different contractile proteins
 Both types overlap to produce a striated (striped) appearance
 Muscle fibres appear to have alternating dark and light bands

Due to arrangement of myofilaments
 Length of muscle fibre is defined by Z
lines that anchor actin
fibres

Area between Z lines is the sarcomere
Thick myosin filaments form darker A band
 Thin actin filaments allow more light to penetrate
• Forms lighter I band

 Muscles cause movement by shortening
 Actin filaments slide over myosin filaments
Z lines move closer together when muscle
fibres contract
 As actin and myosin begin to overlap, lighter I
band becomes progressively smaller

Cause: knoblike projections on myosin forms
cross – bridges on receptors sites of actin
•
Series of cross – bridges attach and detach
as actin filaments are drawn inward
Contraction - http://highered.mcgrawhill.com/olc/dl/120104/bio_b.swf
1
4
2
3
Myosin head
hydrolyzes
ATP to ADP
and Pi.
Myosin head
binds to actin,
forming a
cross –
bridge.
Releasing ADP
and Pi, myosin
relaxes to its low
E state, sliding the
thin filaments.
1
2
3
Binding of
new ATP
releases
myosin head.
4
 Functional Unit of Muscle -Sarcomere by Harvey Project -
http://lessons.harveyproject.org/development/muscle/swstfast.html
 Sarcomere Shortening McGraw-Hill - http://highered.mcgraw-
hill.com/sites/0072437316/student_view0/chapter42/animations.html#
 Sliding Filament theory animation:
http://www.blackwellpublishing.com/matthews/myosin.html
 Muscle structure, sliding filament theory – awesome animations! –
http://www.wiley.com/college/pratt/0471393878/student/animations/acti
n_myosin/actin_myosin.swf
 Energy required for muscle contraction comes from ATP
 In absence of ATP, cross – bridges fail to detach and muscle
becomes rigid
 Rigor mortis
• Due to contraction of muscles following death
• Lasts up to 60 hours after death
 Paralysis

Insecticides may cause paralysis by inhibiting cross –
bridges
 Very little ATP can be stored in muscle tissue
 Energy demand is met by aerobic respiration
Creatine phosphate
Found in muscle cells
 High energy compound
 Ensures that ATP supplies remain high

•
Supplies a phosphate to ADP to replenish ATP
 Should energy demand exceed ATP supply, lactic
acid
will accumulate
 Muscle pain and fatigue
 “Oxygen debt”
• Rapid breathing is designed to repay the oxygen debt
 Occurs when a nerve impulse stimulates several muscle cells
 Latent period
A pause between impulse and muscle contraction
 Muscle contraction:
 Actin and myosin fibres slide over one another
• Muscle shortens
 Muscle relaxation:
 Actin and myosin fibres disengage
• Muscle relaxes (lengthens)
 Should a muscle cell be stimulated once again, it will
contract with equal force

Summation
 Stimulation before
relaxation
• Overlap of actin and
myosin is increased
Greater muscle
shortening
• Sum of 1st and 2nd twitch creates a greater force of contraction
 Strength of contraction depends on how close the second
stimulus is to the first

Repeated muscle stimulation prevents any relaxation phase –
constant state of muscle contraction results in tetanus
 Sprinters

Born with fast twitch muscle fibre
Thick myosin filaments determine speed of muscle
contraction
 3 different forms of myosin, isomers, refer one’s potential
 Type I, IIa, and IIx
•
Type I
Cause slower muscle twitch
 Distance runners

Break down ATP slowly but efficiently
 Rely predominantly on aerobic respiration

Type IIa and IIx
 Fast twitch myosin fibres

Break down ATP faster but less efficiently

Rely predominantly on anaerobic respiration
 Regular exercise and a healthy intake of food are necessary for
maintaining muscles
 Injuries are common among people who perform heavy work or
exercise
 Torn muscles, stretched tendons, torn ligaments, joint
sprains, joint dislocations
Closed and open
bone Fractures
 Used to view torn ligaments
or cartilage
 Needle – like tube,  2 mm
wide
 Equipped with a
fibreoptic light source
 Needle is inserted
through a small puncture
in a knee
• Fibreoptic lens can be
linked to a TV screen
 Can be fitted with thin
surgical tools
• Snip away unhealthy
tissue
 Read section 9.4 in Your Textbook




– pages 298 – 304
Complete Section 9.4 Questions –
Page 304 - #1-7
Fast and Slow Twitch Muscle
Fibres Lab
Muscle tissue microscopic lab
Investigation
Unit Review for Exam


Define Key words on page 307 Text
Chapter 9 Review Questions – 1-22 on
pages 308-309
 Part 1
 1. 4, 2, 3, 1
 2. B
 3. B
 4. B
 5. C
 6. B
 7. 4, 2, 3, 1
 8. 1, 3, 2, 4
 9. W is an alveolus. Alveoli are air sacs in the lung in which
the exchange of gases between the atmosphere and the
blood occurs. X is the trachea. The trachea is the windpipe,
which conducts air from the larynx to the left and right
bronchi. Y is a bronchiole. Bronchioles are the smallest
passageways of the respiratory tract. They terminate in
alveoli.
 10. The trachea, X, has cartilaginous bands.
 11. The inflammation or restriction of the bronchioles, Y, is
associated with asthma.
 12. During inhalation, the diaphragm contracts; the rib cage
moves outward; chest volume increases; lung pressure
drops below that of atmospheric pressure; and air rushes in.
During exhalation, the diaphragm relaxes; the rib cage falls;
chest volume decreases; lung pressure increases over
atmospheric pressure; and air rushes out.
 13. There is comparatively little water in the atmosphere. Cells of the





respiratory tract have a great deal of water, which diffuses into the air held
in the respiratory tract. The forcible expulsion of air during exhalation
releases the water vapour.
14. Oxygen is used by the cells of the body. Blood returning to the lung has
less oxygen; therefore, exhaled air has less oxygen.
15. The increase in water vapour and carbon dioxide in exhaled air will
lower the percentage of nitrogen.
16. (a) The breathing rate would likely be greatest at approximately 2.2 s,
when the level of carbon dioxide is greatest.
(b) The subject began exercising at approximately 1.0 s, when oxygen
levels began to decrease and carbon dioxide levels began to rise.
(c) The breathing rate would return to normal at approximately 3.0 s, when
carbon dioxide levels (the major factor in the regulation of breathing
movements) return to about 40 mmHg—the original resting level. Shortly
thereafter, the breathing rate will drop slightly below normal.
 17. Fetal hemoglobin is more effective at absorbing oxygen. The fetus





secures oxygen from the mother’s blood by way of placental circulation.
Oxygen readily combines with hemoglobin because of its composition;
hemoglobin is composed of four iron molecules and a protein structure,
which allows oxygen to easily bind to the molecule.
18. The following summaries relate to the effects of cigarette smoke on
the respiratory system:
● Destroyed cilia means that fewer particles are prevented from
entering the lower
respiratory tract; thus, more particles accumulate on the walls of the
alveoli, reducing surface area for gas exchange and allowing less oxygen
to diffuse into the blood. When the cilia are destroyed, particles that do
lodge in the sticky mucus of the passageways are not swept into the
back of the throat and are not swallowed, so a cough develops to
dislodge the mucus with the debris.
● Decreased diameter of the bronchioles causes less air to be inhaled
and exhaled with each breath (tidal volume is decreased); therefore, the
oxygen supply is diminished to the body cells and the rate of breathing
would increase.
● Ruptured alveoli walls decrease the surface area available for diffusion
of oxygen and carbon dioxide. Consequently, the breathing rate would
increase.
 19. The sliding filament theory suggests that when a muscle contracts, the




sarcomere shortens as the actin and myosin begin to overlap.
20. Without ATP in the body, the muscle cross-bridges fail to detach, resulting in
permanent muscle rigidity.
21. (a) The motor system moves food through the digestive system using smooth
musclecontraction for peristalsis.
(b) The diaphragm muscle and intercostal muscles can contract and relax to
increase or decrease the volume of the thoracic cavity, resulting in inhalation and
exhalation.
22. Asthma is a disease that has both a genetic and an environmental component.
In recent years, the prevalence of asthma in children has risen significantly,
although there has been no genetic change in the population. This indicates that
asthma in many cases today is due to environmental factors. That is, children
appear to be exposed to more things in the environment to which they are
allergic, and this causes them to develop asthma. Researchers are trying to
identify environmental factors that are causing this trend. Current research
indicates that decreasing exposure to indoor allergens such as dust mites and
environmental tobacco smoke, encouraging breastfeeding, and delaying the
introduction of solid foods are helpful in reducing the risk of a child developing
asthma. Dogs are useful models because their lungs respond in similar ways as
human allergy sufferers do to allergens. Studies can be carried out in dogs that
would be considered unethical in humans. Disadvantages include the fact that
dogs will have some physiological differences to humans in this response and that
many consider research on animals to be unethical.