lab 11 respiration mammalian physiology

8/7/2019 Lab 11 Respiration Mammalian Physiology

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Principles of Human Anatomy and Physiology, 11e 1

LAB 11

Respiratory System


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INTRODUCTION

The two systems that cooperate to supply O2 and eliminateCO2 are the cardiovascular and the respiratory system.

The respiratory system provides for gas exchange.

The cardiovascular system transports the respiratory gases.

Failure of either system has the same effect on the body:disruption ofhomeostasis and rapid death of cells from

oxygen starvation and buildup of waste products.


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Respiratory System Classification

Structurally

Nose

Pharynx = throat

Larynx = voicebox

Trachea = windpipe

Bronchi = airways

Lungs

Functionally

The Conducting System

Consists of a series of cavities and tubes - nose, pharynx,

larynx, trachea, bronchi, bronchiole, and terminal bronchioles- that conduct air into the lungs.

The Respiratory Portion

Consists of the area where gas exchange occurs - respiratory

bronchioles, alveolar ducts, alveolar sacs, and alveoli.


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The Respiratory System

The respiratory system works with the cardiovascular system toaccomplish respiration which includes;

Ventilation (Breathing)-Movement of air in and out of the lungs.

Pulmonary (External) respiration-Exchange of gases between air andblood. Carbon dioxide out to the air, Oxygen into the lungs..

Tissue (Internal) respiration-Exchange of gases between blood andtissue fluids. Oxygen into the tissues and carbon dioxide out of thetissues

Cellular respiration- Production of ATP.


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The Respiratory Tract

It extends from the nose to the lungs As air moves towards the lungs it is cleansed, warmed, and moistened.

Accomplished by hairs, cilia and mucous which act as a screening

device.

Unwanted particles are released as expectorates.

As air moves out during expiration, it cools and deposits moisture on thelining of the trachea and the nose.


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External Nasal Structures

The external portion of the nose is made of cartilage and skin and is

lined with mucous membrane. Openings to the exterior are theexternal nares.

The bony framework of the nose is formed by the frontal bone, nasal

bones, and maxillae.


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Olfactory epithelium for sense of smell Pseudostratified ciliated columnar with goblet cells lines nasal cavity

Warms air due to high vascularity

Mucous moistens air & traps dust

Cilia move mucous towards pharynx

Paranasal sinuses open into nasal cavity

Lighten skull & resonate voice


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The Pharynx

The pharynx (throat) is a funnel-shaped passageway that connects thenasal and oral cavities to the larynx. It also enhances sound.

Three sections.

Nasopharynx - Nasal cavities open above soft palate.

Oropharynx - Oral cavity opens.

Tonsils-lymphoid tissue produce lymphocytes

Laryngopharynx - Opens into the larynx.

The nasopharynx functions in respiration. Both the oropharynx and

laryngoph

arynx function in digestion, respiration and speech

(servingas a passageway for both air and food).


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Pharynx


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The larynx (voice box) serves as a passageway for

air between the pharynx and the trachea..

Thyroid cartilage forms Adams apple Epiglottis---leaf-shaped piece of elastic cartilage

During swallowing, larynx moves upward to prevent food

from entering trachea

Epiglottis bends to cover glottis


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Larynx

The larynx also houses the vocal cords (voice box) whichare stretched across the glottis (opening)

When air passes through the glottis it causes these vocal

cords to vibrate and produce sound.

Tension of glottis determines the pitch High tension-narrow glottis-high pitch

Low tension-wider glottis-low pitchGlottis closed Glottis open


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Trachea

The trachea (windpipe) extends from the larynx to theprimary bronchi.

It is composed of smooth muscle and C-shaped rings of

cartilage and is lined with pseudostratified ciliated columnar

epithelium.

The cartilage rings keep the airway open.

The cilia of the epithelium sweep debris away from the lungs

and back to the throat to be swallowed.

Smoking destroys th

ese cilia


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Trachea and Bronchial Tree

The trachea (windpipe) extends from the larynx to the

primary bronchi.

It is composed of smooth muscle and C-shaped rings of

cartilage and is lined with pseudostratified ciliated columnarepithelium.

The cartilage rings keep the airway open.

The cilia of the epithelium sweep debris away from the lungs

and back to the throat to be swallowed.


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Tracheostomy and Intubation

Reestablish

ing airflow past an airwayobstruction

Crushing injury to larynx or chest

swelling that closes airway

vomit or foreign object

Tracheostomy is incision in trachea below

cricoid cartilage if larynx is obstructed

Intubation is passing a tube from mouth or

nose through larynx and trachea


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Bronchi and Bronchioles

-The trachea divides into the rightand left pulmonary bronchi

-The bronchial tree consists of the trachea, primary bronchi, secondary bronchi, tertiary

bronchi, bronchioles, and terminal bronchioles.

-Sympathetic NS & adrenal gland release epinephrine that relaxes smooth muscle& dilates airways

-Asthma attack or allergic reactions constrict distal bronchiole smooth muscle

-Nebulization therapy = inhale mist with chemicals that relax muscle & reduce

thickness of mucus


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Lungs

The lungs lie on either side of the heart within the thoracic cavity.

Right lung has three lobes and the left lung has two lobes. Each lobe is divided into lobules.


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Alveolar ducts surrounded by alveolar sacs & alveoli

sac is 2 or more alveoli sharing a common opening


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From Airways to the Lungs

Air enters or leaves the respiratory system through nasal cavitieswhere hair and cilia filter dust and particles, blood vessels warm, andmucus moistens, the air

Nose

Pharynx Larynx

Trachea

Bronchi

Bronchioles

Alveoli.


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PULMONARY VENTILATION

Respiration occurs in three basic steps Pulmonary ventilation

External respiration

Internal respiration

The movement of air into and out of the lungs depends on

pressure changes governed in part by Boyles law, which

states that the volume of a gas varies inversely with

pressure, assuming that temperature is constant .


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Respiratory (Lung) Volumes

Measured using a spirometer.

Tidal volume-- the amount of air that moves in and out with each breathduring normal relaxed breathing.

Vital capacity--the maximum amount of air that can be moved in and out in

a single breath.TV +IRV +ERV

Inspiratory Reserve Volume- forced inhalation

Expiratory Reseve Volume--- forced exhalation

Residual Volume The air remaining in the lung after exhaling


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Vital Capacity


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Inspiration and Expiration

Ventilation

Moves of a continuous column of air into and out of lungs

from the pharynx to the alveoli.

Occurs in a cyclic pattern called the respiratory cycle

One respiratory cycle consists of inhalation and

exhalation

Lungs lie within sealed thoracic cavity.

Rib cage forms top and side of the cavity,

while the diaphragm forms the floor..


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Medulla oblongata sets main

rhythm; centers in pons fine-tune it

Magnitude of breathing depends on

concentration of oxygen and H+

Brain detects H+, increasesbreathing

Carotid bodies and aortic bodies

detect drop in oxygen, increase

breathing

brain stem

(pons and

medulla)receptors

detect

decreases in

pH of

cerebrospinal

fluid (due to

rising CO2 in

blood)

carotid bodies

(CO2 receptors)

aortic bodie

(O2 receptor

heart

lungs

spinal chord

Control of Breathing


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Negative feedback control of

breathing

Increase in arterial pCO2

Stimulates receptors

Inspiratory center Muscles of respiration contract

more frequently & forcefully

pCO2 Decreases

Negative Feedback Regulation

of Breathing


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Changes in Pressure

760

756

760

760

754

759

760

756

761

Atmospheric pressure:

Intrapleural

pressure:

Intrapulmonary

pressure:

Before

inhalation

During inhalation

(lungs expanded)

During

exhalation


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Inhalation-Inspiration

Medulla sends neurons tellingdiaphragm to contract and flattens

External intercostal muscles contract

Volume of t

horacic cavity increases Lungs expand

Air flows down pressure gradient intolungs

Negative pressure


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Principles of Human Anatomy and Physiology, 11e 2 9


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FORCED INHALATION

The diaphragm and external intercostals contract Also involves muscles in the anterior regions of the neck

and shoulders


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Normal (Passive) Exhalation

Lung volume decreases

Air flows out of lungs

Diaphragm and the external

intercostals relax Rib cage moves down and

inward

Positive Pressure


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Active Exhalation

Muscles in the abdomen (Rectus Abdominus) and theinternal intercostal muscles contract

This decreases thoracic cavity volume more than passive

exhalation

A greater volume of air must flow out to equalizeintrapulmonary pressure with atmospheric pressure


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Summary of Breathing

Alveolar pressure decreases & air rushes in

Alveolar pressure increases & air rushes out


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EXCHANGE OF OXYGEN AND CARBON DIOXIDE

To understand the exchange of oxygen and carbon dioxidebetween the blood and alveoli, it is useful to know some gas

laws.

According to Daltons law, each gas in a mixture of gases

that exerts its own pressure as if all the other gases were

not present.


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Daltons Law

Each gas in a mixture of gases exerts its own

pressure

as if all other gases were not present

partial pressures denoted as p

Total pressure is sum of all partial pressures

atmospheric pressure (760 mm Hg) = pO2 +

pCO2 + pN2 + pH2O

to determine partial pressure of O2-- multiply 760

by % of air that is O2 (21%) = 160 mm Hg


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Respiration


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Gas Exchanges in the Body

External respiration refers to gas exchange between air inthe lungs and blood in the pulmonary capillaries.

Blood entering the pulmonary capillaries has a higher

partial pressure of carbon dioxide than atmospheric air

Carbon dioxide diffuses out of the blood and red bloodcells into the lungs and released into the air.


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External Respiration

Most carbon dioxide istransported as bicarbonate

The H+ comes from hemoglobin

Bicarbonate formation isenhanced by the action ofcarbonic anhydrase inside red

blood cells


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Opposite for oxygen

Blood entering the pulmonary

capillaries has a lower PP than the

atmospheric air so it diffuses from

the air into the red blood cells and

capillaries

Oxyhemoglobin carries the oxygento the tissues


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O2

and CO2

diffuse fromareas of theirhigher partialpressures to areas of theirlower partial pressures

Diffusion depends on partialpressure differences

Compare gas movements inpulmonary capillaries totissue capillaries


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Internal Respiration

Internal respiration refers to gas exchange between theblood in systemic capillaries and the tissue fluid.

Oxygen diffuses out of the blood into the tissue because

the partial pressure of oxygen of tissue fluid is lower than

that of blood.


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Oxygen diffuses outof the blood into

the tissue

because th

epartial pressure of

oxygen of tissue

fluid is lower than

that of blood.


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Carbon Dioxide is opposite

It diffuses from tissue into blood

10% is dissolved in plasma

30% binds withhemoglobin to form

carbamino hemoglobin

60% percent is in bicarbonate form


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External Respiration vs Internal respiration


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Respiration and Health

Upper Respiratory

Tract

Infections

(Nasal Cavities, Pharynx and Larynx)

Sinusitus

Infection of cranial sinuses.

Congestion blocks the openings leading to pain & post nasaldischarge

Tx: spray decongestives, hot shower, sleep upright

Otitis Media -

Bacterial infection of middle ear.

Nasal infection spreads into auditory tube

Hearing loss, dizziness, fever

Tx: Antibiotics , special tubes


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Tonsillitis Inflammation and enlargement of tonsils.

Tx: If occurrence is often and swelling causes

trouble breathing, they are surgically

removed

Laryngitis Infection of larynx withhoarseness and inability to

talk.


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Lower Respiratory

Tract

Infections

Acute bronchitis -Irritation of the ciliated

epithelium that lines the bronchiole walls

Air pollutants, smoking, or allergies can

be the cause

Excess mucus causes coughing, canharbor bacteria

Chronic bronchitis scars and constricts

airways Infection of primary and

secondary bronchi.

T

x: antibiotics


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Lower Respiratory Tract Infections Pneumonia Viral or bacterial infection of the lungs.

Lungs fill with fluid

Tx: antibiotics

AIDSPneumocystis Carinii


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Restrictive Pulmonary Disorders Vital capacity is reduced because lungs have lost

elasticity.

Coal, sand, dust, asbestos and fiberglass

Pulmonary fibrosis improper inflammation of lungs due to

tissue build-up


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Obstructive Pulmonary Disorders - Air does not flow freely in t

heairways.

Chronic bronchitis

Degenerative breakdown of lungs

Due to pollutants

Tx: stop smoking to slow progression Emphysema

Incurable blockage of alveoli

Preceded by chronic emphysema

Lack of oxygen resulting in irritability & sluggishness

Tx: stop smoking, exercise will slow progression


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Respiration and health

Asthma Immune deficiency causing inflammation of the

bronchioles and bronchi

Wheeziness, breathlessness due to allergens likepollen, dust & smoke

Not curable, but treatable with inhalers

Lung cancer

One of the major causes of death

Generally due to smoking

Begins with the loss of cilia, tumors form &metastasizes


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Effects of Smoking

Shortened life expectancy

Increased rates of cancers

Increased rate ofheart disease

Impaired immune function and healing

Detrimental to fetus


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Principles of Human Anatomy and Physiology, 11e 5 9

Smokers Lowered Respiratory Efficiency

Smoker is easily winded with moderate exercise

nicotine constricts terminal bronchioles

carbon monoxide in smoke binds to hemoglobin

irritants in smoke cause excess mucus secretion

irritants inhibit movements of cilia

in time destroys elastic fibers in lungs & leads to

emphysema

trapping of air in alveoli & reduced gas exchange


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Aging & the Respiratory System

Respiratory tissues & c

hest wall become more rigid

Vital capacity decreases to 35% by age 70.

Decreases in macrophage activity

Diminished ciliary action

Decrease in blood levels of O2

Result is an age-related susceptibility to pneumonia orbronchitis


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lab 11 respiration mammalian physiology

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