BIOL 3542 Lecture Notes - Lecture 17: Pericardium, Rib Cage, Breathing

13 views10 pages

tealspider360

26 Jun 2018

School

University of Manitoba

Department

Biological Sciences

Course

BIOL 3542

Professor

All

For unlimited access to Class Notes, a Class+ subscription is required.

Human Physiology II

Chapter 17: Mechanics of Breathing

The Respiratory System

Cellular Respiration: intracellular reaction of oxygen with organic molecules to produce carbon

dioxide

External Respiration: movement of gases between environment and body cells

4 integrated processes:

1. Ventilation: exchange of air between atmosphere and lungs

oInspiration: movement of air into lungs (inhalation)

oExpiration: movement of air out of lungs (exhalation)

oMechanisms of Breathing: mechanisms by which ventilation takes place

2. exchange of oxygen, carbon dioxide between lungs, blood

3. transport of oxygen, carbon dioxide by blood

4. exchange of gases between blood, cells

Respiratory System: structures involved in ventilation, gas exchange

1. Conducting System: airways that lead from external environment to exchange surface of

lungs

2. Alveoli: series of interconnected sacs, associated pulmonary capillaries that form

exchange surface where oxygen moves from inhaled air to blood, carbon dioxide from

blood to to-be-exhaled air

3. bones, muscles of thorax and abdomen that all assist in ventilation

Upper Respiratory Tract: mouth, nasal cavity, pharynx, larynx

Lower Respiratory Tract: trachea, 2 primary bronchi and their branches, lungs

a.k.a. thoracic portion of respiratory system because it’s enclosed in the thorax

Bones and Muscles of the Thorax Surround the Lungs

thorax bounded by bones of spine, rib cage, their associated muscles

Thoracic Cage: bones, muscles together

2 sets of intercostal muscles, internal and external, connect 12 pairs of ribs

sternocleidomastoid, scalene muscles run from head, neck to 1st 2 ribs

pericardial sac contains heart

pleural sacs each surround a lung

esophagus, thoracic blood vessels, nerves pass between pleural sacs

Pleural Sacs Enclose the Lungs

Lungs: light, spongy tissue, volume occupied by air-filled spaces

cone-shaped

nearly fill thoracic cavity

bases rest on diaphragm

bronchi connect lungs to trachea

each lung surrounded by double-walled pleural sac, membranes line inside of thorax, cover

outside of lungs

find more resources at oneclass.com

Unlock document

This preview shows pages 1-3 of the document.
Unlock all 10 pages and 3 million more documents.

Already have an account? Log in

pleura contain several layers of elastic connective tissue, numerous capillaries

opposing layers held together by thin film of pleural fluid

pleural fluid creates moist surface so opposing membranes can slide across one another as

lungs move, holds lungs tight against thoracic wall

Airways Connect Lungs to the External Environment

air flows from pharynx, through larynx to trachea

larynx contains vocal cords, connective tissue bands that vibrate, tighten to create sound

when air moves past

Trachea: semi-flexible tube held open by C-shaped cartilage rings, extending down into thorax

branches in pair of primary bronchi, 1 in each lung

Bronchi: semi-rigid tubes supported by cartilage

branch repeatedly in lungs into progressively smaller bronchi (bronchioles)

Bronchioles: small, collapsible passageways with walls of smooth muscle

continue branching until respiratory bronchioles form transition between airways,

exchange epithelium of lung

total cross-sectional area increases with each division of airways

lowest in upper respiratory tract, greatest in bronchioles

velocity of air flow inversely proportional to total cross-sectional area of airways

greatest in upper airways, slowest in terminal bronchioles

The Airways Warm, Humidify, and Filter Inspired Air

upper airways, bronchi condition air before it reaches alveoli

3 components of conditioning:

1. warming air to body temp. (37oC) so core body temp. doesn’t change, alveoli aren’t

damaged by cold air

2. adding water vapour until air reaches 100% humidity, so moist exchange epithelium

doesn’t dry out

3. filtering out foreign material so viruses, bacteria, inorganic particles don’t reach alveoli

breathing through mouth not as effective at warming, moistening air as breathing through

nose

air filtered in trachea, bronchi lined with ciliated epithelium whose cilia bathed in watery

saline layer produced by epithelial cells with chlorine ions secreted into lumen by apical

anion channels draw sodium ions into lumen through paracellular pathway

movement of solute from ECF to lumen creates osmotic gradient, water follows ions into

airways

CTFR channel one ion channel found in apical surface of epithelium

sticky mucus layer secreted by goblet cells in epithelium floats over cilia to trap inhaled

particles

contains immunoglobulins that disable many pathogens

Mucociliary Escalator: cilia beat in upward motion that moves mucus towards pharynx

once reaching pharynx, mucus can be spit out (expectorated) or swallowed

stomach acid, enzymes destroy remaining microorganisms

in cystic fibrosis, inadequate ion secretion decreases fluid movement in airways

find more resources at oneclass.com

Unlock document

This preview shows pages 1-3 of the document.
Unlock all 10 pages and 3 million more documents.

Already have an account? Log in

without saline layer, cilia become trapped in thick, sticky mucus, cannot move

mucus cannot be cleared, bacteria colonize airways resulting in recurrent lung infections

Alveoli Are the Site of Gas Exchange

air-filled alveoli, clustered at ends of terminal bronchioles, make up bulk of lung tissue

primary function is gas exchange between themselves, blood

each alveolus composed of single layer of epithelium

type I alveolar cells, larger cells used for gas exchange

layer of basement membrane fuses alveolar epithelium to capillary endothelium

remaining area filled with small amount of interstitial fluid

smaller, thicker type II alveolar cells synthesize, secrete chemical surfactant that mixes

with thin fluid lining of alveoli to aid lungs as they expand during breathing

minimize amount of fluid present in alveoli by transporting solutes, followed by water,

out of alveolar air space

thin walls of alveoli don’t contain muscle, would block rapid gas exchange, so lung itself

cannot contract

connective tissue between alveolar epithelial cells contains elastin, collagen fibers that

create elastic recoil when lung tissue stretched

blood vessels fill space between alveoli, forming “sheet” of blood in close contact with air-

filled alveoli, allowing for rapid gas exchange

Pulmonary Circulation Is High-Flow, Low Pressure

pulmonary trunk gets low-oxygen blood from right ventricle, divides into 2 pulmonary

arteries, 1 to each lung

oxygenated blood from lungs returns to left atrium via pulmonary veins

rate of blood flow through lungs much higher than in other tissues

as much blood flows through lungs in 1min than through rest of body in same amount of

time

pulmonary blood pressure low

right ventricle doesn’t have to pump as forcefully to create blood flow through lungs because

resistance of pulmonary circulation low

attributed to shorter total length of pulmonary blood vessels, distensibility, large total

cross-sectional area of pulmonary arterioles

normally net hydrostatic pressure filtering fluid out of a pulmonary capillary into interstitial

space low because of low mean blood pressure

lymphatic system removes filtered fluid, lung interstitial fluid volume minimal, resulting in

short distance between alveolar air space, capillary endothelium, allowing rapid diffusion of

gases between them

Gas Laws

Air Is a Mixture of Gases

Dalton’s Law: total pressure exerted by mixture of gases is sum of pressures exerted by

individual gases

Partial Pressure (Pgas): pressure of single gas in mixture

find more resources at oneclass.com

Unlock document

This preview shows pages 1-3 of the document.
Unlock all 10 pages and 3 million more documents.

Already have an account? Log in

Document Summary

Cellular respiration: intracellular reaction of oxygen with organic molecules to produce carbon dioxide. External respiration: movement of gases between environment and body cells. 3. transport of oxygen, carbon dioxide by blood: exchange of gases between blood, cells. Upper respiratory tract: mouth, nasal cavity, pharynx, larynx. Lower respiratory tract: trachea, 2 primary bronchi and their branches, lungs. A. k. a. thoracic portion of respiratory system because it"s enclosed in the thorax. Bones and muscles of the thorax surround the lungs thorax bounded by bones of spine, rib cage, their associated muscles. 2 sets of intercostal muscles, internal and external, connect 12 pairs of ribs sternocleidomastoid, scalene muscles run from head, neck to 1st 2 ribs pericardial sac contains heart. Pleural sacs each surround a lung esophagus, thoracic blood vessels, nerves pass between pleural sacs. Lungs: light, spongy tissue, volume occupied by air-filled spaces.

Related Questions

12. Passive expiration is preceded by the:

a. recoil of the lungs

b. contraction of the internal intercostals muscles.

c. contraction of the diaphragm.

d. increase in atmospheric pressure.

e. increase in CO₂ in the blood

14. Type I alveolar cells:

a. secrete surfactant.

b. are squamous epithelial cells.

c. are macrophages.

d. function mainly in the diffusion of gases.

e. Both B and D.

15. Which of the following structures is NOT a part of the respiratory system?

a. external nares

b. uvula

c. epiglottis

d. choanae

e. mouth

19. Which of the following is NOT considered a function of the respiratory system?

a. Regulation of acid-base balance

b. Production of sound

c. Filtering inspired air

d. Transport of oxygen and carbon dioxide to tissue cells

e. Intake of oxygen and elimination of carbon dioxide

20. Breathing is more difficult in higher altitudes because the

a. air weighs less

b. partial pressure of atmospheric oxygen is lower

c. partial pressure of atmospheric carbon dioxide is higher

d. partial pressure of atmospheric nitrogen is lower

e. partial pressure of atmospheric oxygen is higher

27. During expiration a decrease in thoracic cavity size causes a (an) in pressure thus causing the lungs to recoil resulting in a (an) in pressure respectively.

a. decrease intraplueral; decrease intrapulmonary

b. decrease intraplueral; increase intrapulmonary

c. increase intraplueral; decrease intrapulmonary

d. decrease intrapulmonary; increase intraplueral

e. increase intrapleural ; increase intrapulmonary

66. During _____________ ______________, oxygen enters the blood and carbon dioxide leaves the blood, and enters the alveoli.

68. Hemoglobin buffers the pH of the cytosol of RBC by combining with ______ions

Background

Almost all animal and plant cells require oxygen and give off carbon dioxide. This is called gas exchange and it occurs by passive diffusion. Some animals do all or most of their gas exchange across their skin (for example amphibians) but they have very low metabolisms and use very little oxygen and get rid of very little carbon dioxide.

On the other hand humans (and other mammals) have very high metabolic requirements and we canât rely on gas exchange over the limited 1.5 to 2.0 square meters of our skin to get enough oxygen in and carbon dioxide out fast enough. Our gas exchange takes place across a very thin membrane in the Alveoli of the lung and the gas exchange surface in humans is estimated to be between 50 and 100 square meters, or between 25 and 67 times our skin surface area.

Our lungs provide a huge surface for gas exchange but they are a dead-end system. Once the oxygen in the lungs is used up it needs to be replenished and carbon dioxide builds up in the air spaces in the lungs and needs to get out. This is where the diaphragm and a few of the skeletal muscles become important. In its relaxed state the diaphragm is at its longest and the space in the thoracic cavity (and the lungs) is small. When the diaphragm contracts it shortens, which increases the volume of the thoracic cavity (and the lungs). The increase in size means the pressure is lower in the lungs than outside so air comes into the lungs (inhalation). As the diaphragm relaxes, the lungs decrease in size enough that the pressure inside the lungs is higher than the external air pressure so air comes out (exhalation).

Introduction

In this lab you will be building a model of a lung and experimenting with different ways to breath.

Supplies:

In the Lab Kit

One round 9" balloon (one lung, we donât need two for this)
medium-sized plastic bag large enough to fit over bottom end of bottle (diaphragm)
medium-size, thin rubber band

You supply

plastic 2-liter soda bottle with bottom cut off (thoracic cavity)

Tape (optional)

Directions:

1. Insert the balloon through the open bottom of a modified 2-liter soda bottle and up over the neck of the bottle. Pull the end of the balloon over the edges of the neck of the bottle. The balloon is held open by the neck of the bottle.

2. Place the plastic bag over the bottom (open) end of the 2-liter bottle and use the rubber band to hold it in place. This will serve as the diaphragm. To inflate the lung, blow into the balloon just before you fasten the rubber band. You can also wrap tape over the edges of the plastic bag to minimize air leaks

3. Grasp the bottom of the plastic bag and pull it down and push it up. Watch as the "lungs" (the balloon) expand and contract as you do this. The balloon has to change size because the air space between the balloon and bottle must remain constant. (Well, it would if the seal around the plastic bag and bottle were perfect).

You may block the "trachea" (the neck of the bottle) so that the air supply is cut off and watch as nothing happens when the "diaphragm" is pushed in and out.

This model isnât perfect. None of the joints are air tight as they would be in a real thoracic cavity. Pull the âdiaphragm down and watch the lungs expand . If you hold it in place, the lungs will collapse again over time. This is because of leaks and is not how real lungs work. Pushing the diaphragm in and pulling it out over and over does give you an idea of how lungs work. As the diaphragm tightens, contracts (pull down on the plastic bag) the lungs fill with air. As the diaphragm relaxes (push up on the plastic bag) air is expelled from the lungs .

There are several different ways we breath, i.e. expand our thoracic cavity so that our lungs can expand. You have just made a demonstration model of the diaphragm at work. You can also use your rib cage to expand and contract so that you can inhale and exhale. There are muscles between and around your ribcage which you can use to change the size of your thoracic cavity.

This is approximately what your model of a lung will look like.

Answer the questions on the Report Page

Report Page Name

1. Put a hand on your lower ribcage and try moving your ribs out and in. Does air also move in and out?

2. Someone with an upper back or neck injury may not have the options of using diaphragm or ribs to breath. They can learn to use the clavicle and the muscles attached to expand their thoracic cavity a small amount and breathe independently for short periods of time. Put your hand on you clavicle and try to raise and lower just that bone without using your diaphragm or your ribs. It isnât easy but you should be able to get a little air into and out of your lungs this way. How effective do you think this way of breathing is?

3. When you take a really deep breath you use all these muscle groups to help. Take a really deep breath and notice that your ribs expand, your lower abdomen comes out (a sign that the diaphragm has contracted) and your shoulders lift a little (the upper chest and clavicle are working). Now take a relaxed breath. Only your abdomen should go in and out. The movement of your abdomen is a result of the contracting diaphragm pushing on the contents of your âgutâ which forces your abdomen to push out.

Do you breath in or out when your diaphragm contracts?\

4. If a hole were poked in your thoracic wall (the wall of the pop bottle â the hole should be at least the diameter of a pencil)

a. what would happen when you tried to breath? (This is a pneumothorax).

b. Is the space between the balloon and plastic bottle still required to remain constant?

5. Would it be possible to live with a paralyzed diaphragm? Explain your answer.

fuchsiamuskrat152

1. Which of the following are considered blood vessels within the cardiovascular system? (Select all that apply.)

Veins

Arteries \

Epithelial tissue

Capillaries

Epidermis

2. The middle muscle layer found in the walls of the heart is the __________.

Myocardium

Epicardium

Endocardium

Aorta

3. Blood is transported throughout the body via ___________.

Veins
Arteries

Capillaries

All of the above

4. The right atrium receives blood from all parts of the body except the ______________.

Abdominal cavity

Lungs

Dorsal cavity

Cranium

5. Blood carries which of the following?

Oxygen and cellular waste

Oxygen, nutrients, hormones, enzymes, and cellular waste

Nutrients, hormones, enzymes

Oxygen, nutrients, enzymes

6. Vocal chords are found in the ____________.

Bronchus

Trachea

Larynx and Pharynx

Nasal cavity

7. The trachea is mostly lined by ________________.

Alveoli

Ciliated

mucous membrane

Lung capillaries
Vocal chords

8. Excess CO2 from the body is __________________.

Stored in the pancreas

Digested by cells

Excreted by the respiration process

Used to make ATP

9. CO2 from the body is released into the lungs via _________________.

Ciliated mucous membrane

Alveolar air

Nasal cavity

Bronchial tree

10. The principal function(s) of gas exchange is ____________________.

To supply cells with oxygen

To remove CO2 from the body

Both A and B

Neither of the above

One of the most common chronic conditions affecting the respiratory system is asthma. Asthma is a condition characterized by inflammation of the airways. When an asthma attack is triggered, the airways become even more inflamed and can restrict breathing. Common symptoms during an asthma attacks include coughing, wheezing, tightness in the chest and shortness of breath. Severe asthma attacks can be fatal. People with a family history of asthma are more likely to have the condition. While there is no cure for asthma, proper medical care and a management plan can help to maintain quality of life for people living with asthma. There are different types of asthma, each with their own triggers and management plans. Type Description Exercise-induced Bronchoconstriction (EIB), or Exercise-induced Asthma (EIA) Some people only experience asthma symptoms during exercise. Exercise-induced asthma causes the narrowing of airways during exercise, which restricts the flow of air to and from the lungs. Cold, dry air tends to exacerbate symptoms, while warm, humid air may reduce symptoms. People with exercise-induced asthma should work with their doctor to create a management plan that still allows them to exercise while keeping their symptoms under control. Allergic Asthma Allergic asthma is the most common form of asthma. It is triggered by inhaling allergen particulates, such as dust mites, pollen, pet dander, or mold. The bodyâs reaction to the allergens causes inflammation that results in coughing, wheezing, and other symptoms of asthma. Occupational Asthma Occupational asthma is caused by the frequent inhalation (breathing) of gases, fumes, dust, or other harmful substances in the workplace. Employees working in the chemical or petroleum industries are frequently exposed to chemicals such as Sulphur dioxide or hydrochloric acid, and may develop occupational asthma after prolonged exposure. Childhood Asthma Childhood asthma is usually developed before age 5. It is a condition that affects millions of children. It is vital that childhood asthma is properly controlled to prevent damage to the developing lungs Risk factors: â¢ Allergies â¢ Family history â¢ Frequent respiratory infections â¢ Low birth-weight â¢ Second-hand smoke â¢ Residing in a low-income, urban environment

Asthma symptoms that are triggered by exposure to pollen, pet dander, mold, or dust mites is indicative of which of the following types of asthma:

Occupational asthma

Childhood asthma

Allergic asthma

Exercise-induced asthma

aquamarinecaribou889

BIOL 3542 Lecture Notes - Lecture 17: Pericardium, Rib Cage, Breathing

Document Summary

Get access

Related Documents

BIOL 3542 Lecture Notes - Lecture 8: Cytosol, Ph, Osmotic Concentration

BIOL 2420 Lecture Notes - Lecture 1: Respiratory Tract, Intercostal Muscle, Thoracic Wall

314151 Lecture Notes - Lecture 4: Respiratory System, Trachea, Partial Pressure

Related Questions