Transcript Respiration: Anatomy

Respiration: Anatomy
• Respiration = process of gas exchange
between the organism and environment.
Oxygen taken in during inspiration;
waste products (e.g., CO2) expelled
during expiration.
• 1. RESPIRATORY PASSAGE
• Composed of nasal and oral cavities,
pharynx, larynx, trachea, and bronchi
• Functions:
trachea
Trachea
• For a simple video of how respiration works,
click on the button from argosymedical.com
http://science.nationalgeographic.com/science/health-and-human-body/human-body
– A. Larynx: specialized valvular mechanism; can open
or close the air passageway.
– Biological function:
• Protective device Google “Vocal folds and cough”
• Thoracic fixation: needed to increase abdominal
pressure to evacuate visceral contents.
– When is fixation used?
– B. Trachea: muscular tube
• extends from larynx to bronchi
• 11 to 12 cm in length and between 2-2.5 cm in
diameter
• composed of 16 to 20 horseshoe-shaped rings of
hyaline cartilage
– Each ring separated by sm. space of
fibroelastic membrane.
– Each ring is incomplete posteriorly where
trachea lies in contact with esophagus-fibrous tissue and muscle are in space
between ends
– Cartilaginous structure allows for
rigidity to prevent collapse, while
posterior structure (muscle &
membranes) provide flexibility &
mobility that permit it to be
stretched (e.g., during inhalation),
twisted, or compressed.
Trachea cont.
http://www.youtube.com/watch?v=sU_8juD3YzQ
http://video.google.com/videosearch?q=cilia&hl=en&emb=0#q=human%
20respiration&hl=en&emb=0&start=20
– Functions:
» How are these accomplished?
» Hyaline rings stiffen structure to help
keep it open.
» Trachea lined with ciliated epithelial
mucous membrane, secretes mucous to
moisten incoming air; cilia are in constant
motion, beat @ 10X-20X per second, at
first downward, then slowly upward
– Clinical note: One of major causes of lung
infection is reduced ciliary action. Normally
the mucous blanket lining trachea is propelled
toward larynx at rate of 5mm per minute.
Smoke from a single cigarette can cause cilia
to be non-motile for several hours. At the
same time cigarette smoke stimulates mucus
secretion.
– Cilia begin to repair and regenerate only 3
days after smoking ceases, although the
complete process takes @ 7 years. Some
damage can be permanent.
– CLINICAL NOTE: An emergency
operation called tracheostomy (tome
= cutting) is sometimes performed
because of such things as
obstruction of upper airway due to
inflammatory disease or food lodged
in larynx. Incision is made in
anterior neck, usually between 2nd
and 3rd tracheal cartilages.
Opening into trachea called
tracheostoma (stoma = mouth). See
next slide
– C. Bronchi: tubes extending from trachea
to lungs where they arborize (branch) to
form bronchial tree.
– Bronchi divided into three groups:
• 1. main or main stem bronchi
• 2. lobar or secondary bronchi (supply
lobes of lungs)
• 3. segmental or tertiary bronchi (supply
segments of lobes)
• 1.
Main bronchi:
is larger than
• Structure similar to trachea (e.g., imperfect
cartilaginous rings, lined with ciliated epithelial
lining). Right bronchus divides into three
secondary bronchi (one for each lobe) and into 10
tertiary bronchi. Left divides into 2 secondary
and then 8 tertiary.
• 2. Bronchioles: In adult there are about 24
generations of divisions in the bronchial tree.
Final division gives rise to bronchioles, tubes are 1
mm or less in diameter. Repeated divisions of
bronchioles give rise to terminal bronchioles which
communicate with alveolar ducts, which open into
minute air sacs.
• 3. Alveoli: The terminal bronchioles and air sacs
are pitted with around 7,000,000 small
depressions call alveoli. The alveolar wall is
invested with capillary network (about 1,000 miles
of capillaries—e.g., from Dayton, OH to Orlando).
Capillaries separated from air by barrier of less
than 1/3 diameter of red blood cell. Total alveolar
area in contact with capillaries is @ size of tennis
court. Thin barrier and immense area facilitate
rapid exchange of oxygen and carbon dioxide.
•
Alveoli cont.
• Alveoli contain Type I (simple squamous
epithelium) cells and Type II cells (produce
surfactant). Lining also contains Phagocytic cells,
also called alveolar macrophages (ingest dust,
bacteria, and other debris--are also injured by
smoke).
• Simple squamous epithelial cells permit:
• Exchange of gases between the air in the lungs and
the blood in the capillaries occurs across the walls
of the alveolar ducts and alveoli.
• Surfactant: any substance that reduces the
surface tension. See next slide.
• Alveoli properties: Epithelial lining keeps tissue
moist thru secretions. Surface tension exists due
to attraction of molecules for one another. The
force causes liquid lining to behave like stretched
elastic, it tries to shorten and resist further
stretching.
• Surface tension accounts for tendency of alveoli
to collapse, and this tendency to collapse is
responsible for 2/3 of elasticity of lungs. The
Type II cells produce surfactant which acts like
detergent, decreasing surface tension.
Surfactant proteins have also been found to be
part of the defensive mechanism that helps fight
pathogens (infections) and inflammation.*
• CLINICAL NOTE: Consequences of insufficient
surfactant production is respiratory distress syn.
or infant respiratory distress syndrome
(formerly called hyaline membrane disease) which
affects premature babies. Type II cells are too
immature to produce enough surfactant in these
cases. Infant able to inspire only by exhaustive
efforts due to lung resistance to expansion. Can
result in respiratory failure, lung collapse and
death. Medical Tx: administer cortisol to
pregnant women OR surfactant replacement tx.
FYI
– D. Lungs www.innerbody.com (cardiovascular
system; animations)
– Biological Function: breathing for life, protection for
heart and for removal of wastes and toxins.+
– located in thoracic cavity (chest).
• Thorax houses lungs, heart, great blood vessels,
esophagus.
– 2 irregularly cone-shaped structures--composed of
spongy, porous, highly elastic material.
– When handled in a cadaver, sound like crumpling tissue
paper (due to presence of air within the alveoli).
– White in color at birth, become progressively darker.*
See next slide
– R lung larger, but shorter and broader (due to liver
occupying R abdominal cavity forcing dome of
diaphragm higher on R side). Heart occupies L side of
thorax, thus smaller L lung lobe.
– Contains few muscle fibers. Thus lung tissue is
passive, cannot exert force except by elastic
properties. 1/4-1/3 of elasticity of lung due to lung
tissue properties. Remainder of elasticity due to
alveoli.
Normal lung
Filter before and
after particulate
testing, Italy
cancer
emphysema
Non-smoker, smoker
– Each day you breathe about 25,000 times, and by the
time you're 70 years old, you'll have taken at least 600
million breaths. *
– The Pleurae: inner surface of thoracic cavity, thoracic
surface of diaphragm, & mediastinum (space between R
and L lungs; median partition of thoracic cavity) are
lined with a membrane called parietal or costal pleura.
The visceral pleura lines the lungs. SEE NEXT SLIDE
• 2 types of pleurae
1. costal (parietal)
2. Visceral
NOTE: liquid located between pleurae to form
bond.
• FUNCTION: (a) provides friction-free lung and
thoracic surfaces. The two moist surfaces glide
on one another with every breathing cycle. The R
and L pleural sacs are completely separated. The
mediastinum between them contains heart, blood
vessels, and esophagus.
Blue = costal; pink = visceral pleura
CLINICAL NOTE: pneumothorax-puncture of one lung, resulting in
collapse. Done medically for Tx of
tuberculosis or similar illnesses.
Collapsed lung benefits from rest
received. After closing the opening,
the lung slowly expands.
• Pleurae mechanics: Lungs have tendency to
collapse and pull away from thoracic walls due to:
– (a) inherent elasticity of lung tissue+ (b)
surface tension in fluid lining of alveoli
produces tendency to collapse.
• -Through pleural linkage (of pleural membranes-negative pressure created in intrapleural spaces
by absorption of gases and fluids and bounds two
pleurae by intrapleural fluid pressure) to thoracic
walls, lung surfaces are held tightly in contact with
inner surface of thoracic walls.
• Inhalation: lungs expand due to chest cavity
enlarging; during exhalation elasticity of lungs
takes over, creating increased recoil, and lungs
return to unexpanded state.
Using your knowledge about pleural mechanisms,
what would be the symptoms of the individual who
has lungs as shown on the right?
• www.getbodysmart.com; look at tutorials on
respiration, trachea through lungs, and take
quizzes on these sections.
•
Please go through the video presentation as
shown below and as listed on Webcourses in
the file Respiration Website.
• http://lgfl.skoool.co.uk/content/keystage4/biology/
pc/lessons/uk_ks4_breathing_and_respiration/hframe-ie.htm
Respiratory Framework
• Principle framework:
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spinal or vertebral column
Ribs
Pectoral girdle
Sternum
Pelvic girdle
http://www.anatomy.wright.edu/QTVR/index.html
– A. Spinal column: 32-33 vertebrae joined
together by intervertebral cartilage and
ligaments (fibrous connective tissue which
connects bones or holds organs in place).
– Types of vertebrae: often identified by
letter (type) & number (position) C5, L4
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7 cervical (cervix = neck)
12 thoracic (chest)
5 lumbar (loin)
5 sacral (sacred)--fit together, appear
to be one bone called sacrum
• 3-4 coccygeal (cuckoo--suppose to
resemble the beak of a cuckoo)-vestigial (sm. degenerate or incompletely
developed structure which was more
fully dev. in previous stage of species)-usually thought of as individual
structure called coccyx.
• See next slide
• www.apparelyzed.com/spinalcord.html
• Myotomes and disability
FYI
•
Myotomes - Relationship between the spinal nerve & muscle
•
Dermatomes - Relationship between the spinal nerve & skin.
•
Each muscle in the body is supplied by a particular level or
segment of the spinal cord and by its corresponding spinal
nerve. The muscle, and its nerve make up a myotome. This
is approximately the same for every person and are as
follows:
C3,4 and 5 supply the diaphragm (the large muscle between
the chest and the belly that we use to breath).
C5 also supplies the shoulder muscles and the muscle that
we use to bend our elbow .
C6 is for bending the wrist back.
C7 is for straightening the elbow.
C8 bends the fingers.
T1 spreads the fingers.
T1 –T12 supplies the chest wall & abdominal muscles.
L2 bends the hip.
L3 straightens the knee.
L4 pulls the foot up.
L5 wiggles the toes.
S1 pulls the foot down.
S3,4 and 5 supply the bladder. bowel and sex organs and
the anal and other pelvic muscles.
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– Types of vertebrae:
• cervical vertebrae:
– Atlas (C1) = skull rests on atlas (Greek
mythology giant Atlas had to bear the wt. of
sky-punished by Zeus)-shaped like ring--anterior and posterior tubercles=imp.
landmarks in radiographic exam of sp. mech.
– Axis (C2) = forms pivot @ which altas and
skull rotate--landmark dens (tooth) or
odontoid (toothlike) process--is projecting
cranially (see next slide)
– C7 = conspicuous spinous process which can
usually be palpated at base of neck
• thoracic vertebrae: provide pts. of attachment
for ribs--increase in size from T1 to T12
• lumbar = very lg.--Wt. bearing function
– Spinal curves: discs which are between vertebrae in
the cervical and lumbar regions are thicker anteriorly
than posteriorly, creating concave curvature of the
spine in those areas. In thoracic region, discs are
same thickness, however, bodies of vertebrae are
slightly thinner in front than in back creating a convex
curvature.
• CLINICAL NOTE: Abnormal curvatures of spine
– kyphosis: hunchback--increased convex
curvature in thoracic verte.--sometimes
caused by tuberculosis in vertebral bodies,
bodies become eroded, weakened, and
distorted by wt. of body. Poor posture and m.
imbalance may also be contributing factors.
Kyphosis can inhibit rib cage movement and
reduce pulmonary compliance.
– lordosis: swayback--caused by TB, poor
posture, or prolonged wearing of excessively
high heels.
– scoliosis: abnormal lateral curvature--caused
by muscle imbalance, poor posture, diet,
paralysis.
•
Respiratory framework cont.
– B. Sternum or breastbone--3 parts: manubrium
(handle), body, xiphoid process (sword)
• manubrium: articulates with clavicle (collarbone)
and with 1st costal cartilages of ribs
– C. Ribs: The rib cage = 12 pair of ribs--ribs
designated by numbers--First 7 ribs course obliquely
downward from the vertebral column (in infant ribs are
more horizontal). At their lowest pt., the osseous ribs
give way to costal cartilages which course upward to
articulate with the sternum. In old age, the cartilages
ossify superficially, reducing the compliance of the rib
cage.*
– CLINICAL NOTE: extra ribs, esp. on C7, are not
uncommon and may cause discomfort and pain. A rib on
L1 may cause back problems.
• Ribs cont.
– First 7 ribs articulate with sternum = true
ribs or vertebrosternal
– Next 3 pairs (8, 9, 10) are connected
indirectly with sternum by long costal
cartilages = false ribs or vertebrochondral
ribs (chrondral = pertaining to cartilage)
– Last 2 have vertebral attachments, but
anterior extremeties are free = vertebral
or floating ribs
– Movements in breathing: During inhalation,
the dimensions of the thoracic cavity
increases in 3 planes: vertically (diaphragm
contracts), transverse (raising of curved
ribs), anteroposterior (simultaneous
forward and upward movement of sternum)
– D. Pelvic girdle: hip bone (or coxal bone), sacrum and
coccyx
– Function for speech = abdominal wall muscles attach to
hip bone and pelvis is "floor" for abdominal viscera.
– CLINICAL NOTE: for most pts. with cerebral palsy,
proper positioning of the pelvis is crucial to
maintanence of breath support for speech.
– E. Pectoral (breast) girdle: clavicle and scapula
MUSCULATURE OF BREATHING
MECHANISM
•
Muscles of inhalation are mainly in the thorax; muscles
of exhalation primarily in abdomen.
1.
Muscles of thorax:
(A) diaphragm
(B) external intercostals
(C) internal intercostals
(D) transversus thoracis
(E) costal elevators, and
(F) serratus posterior, superior, and inferior
•
A. Diaphragm: (means = partition, wall, barrier). It is
the main muscle for breathing (inspiration).
Separates thorax (lungs, heart, structures in
mediastinum) from abdomen (filled with digestive tract).
Thin but very strong
Dome-shaped, like inverted bowl
May be most important muscle in body next to heart.
Unpaired muscle
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• www.kidshealth.org/kid/body
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Origin at xiphoid process of sternum, inner surface of ribs
7 - 12, upper lumbar vertebrae posteriorly. Fibers course
upward and inward, inserting into central tendon.
•
When we inhale, the diaphragm moves downward toward
the abdomen, and the rib muscles pull the ribs upward and
outward, enlarging the chest cavity and pulling air in
through the nose or mouth.
•
When we exhale, the diaphragm moves upward (relaxes),
forcing the chest cavity to get smaller and pushing the
gases in the lungs up and out of the nose and mouth.
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Air pressure :
•
ACTION=when rim contracts, pulls diaphragm downward
and slightly forward, thus increasing thorax in vertical
direction. Contraction compresses abdominal contents.
There may be expansion of abdominal wall-sometimes called
abdominal or diaphragmatic breathing. Contraction also
increases circumference of thoracic cavity through
elevation of lower ribs.
• B. External Intercostal muscles:
• More prominent and stronger than internal
intercostals
• 11 in number
• Originate at lower surface of a rib; course
downward and laterally; terminate near
chondro-osseous union of ribs and cartilage
• ACTIONS= elevate rib below, thus increasing
the anteroposterior and transverse dimensions,
during inspiration.
• They tense rib interspaces, preventing them
from being sucked inward during inspiration.
• Are inactive during expiration on quiet
breathing, however, are active during forced
exhalation.
• Conclusion: They are active mainly during
inspiration.
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C. Internal Intercostal muscles
lie deep to external
11
Course from anterior limits of intercostal space
(immediately lateral to the sternum) to angle of rib
posteriorly (pt. where rib abruptly changes direction).
Originate on the superior portion of a rib; course medially;
and insert on the next rib above.
– This course is opposite to external intercostals.
THUS, area lateral to vertebral column is devoid of
internal intercostals and the area lateral to the sternum is
devoid of external intercostals.
ACTION=
– Intercartilaginous portion = inspiratory in function
(elevating ribs, especially during forced inspiration).
– Interosseous portion= pull ribs downward and stiffen
rib interspaces--aids in exhalation--probably active
during speech production.
CONCLUSION: Aid prolonged and forced exhalation
Note the lack of external intercostals near the
sternum and the termination of the internal
intercostals (they never reach the vertebral
column)
Which arrows are pointing to the ending points or
terminations of the internal intercostals? Which
are pointing to the end point of the external
intercostals?
– Summary of intercostal action
• Intercostal muscles are major contributors to
inspiration. One can still produce an adequate level
of pulmonary ventilation with just intercostal
muscles, if the diaphragm is paralyzed.
• In general, they produce rib movements during
inhalation, and contribute to the rigidity of the
thoracic wall by preventing intercostal spaces
from being pulled in and out during breathing. Also
help control the amount of space between ribs; and
they couple ribs, one to another, so that movement
of one rib will influence position of adjacent ribs.
• Both are active during non-passive/active
expiration (forced = external; prolonged = internal)
• D. Transversus Thoracis muscles (deep to
intercostals)
• Located on inner surface of anterior thoracic
wall. Originate from posterior body of sternum
& post. surface of xiphoid process & post.
surfaces of chrondral portions of ribs 5 - 7.
Insert into lower borders and inner surfaces
of ribs 2-6.
• ACTION: Depress ribs to aid in exhalation
• E. Costal Elevators: 12 on ea. side--arise
from C7 and upper 11 thoracic vertebrae-course obliquely downward and laterally--insert
at angle of rib--ACTION: elevate ribs during
inhalation (see below)
• F. Serratus posterior superior: Arises from
spinous process of C7 & T1,2--courses
downward & obliquely--inserts on ribs 2-5-ACTION: may elevate ribs
• G. Serratus posterior inferior: Arises from
spinous process of T11& T12, & L1,2,3--courses
upward & obliquely--inserts on ribs 8-12-ACTION: probably exerts downward press. on
lower ribs during forced exhalation.
• 2. Muscles of neck:
• Sternocleidomastoid and scalenes [means
“uneven”]
• A. Sternocleidomastoid
• originates from 2 heads—
– sternal head= anterior surface of manubrium of
sternum;
– clavicular head= superior surface of sternal end
of clavicle--fibers course upward, 2 heads unite.
– Inserts as single m. into mastoid process of
temporal bone
– ACTION: unilateral contraction= draws side of
head toward shoulder and rotates it. Bilateral
contraction tends to flex neck toward thorax.
When head in fixed position, muscle may raise
sternum and clavicle to assist in inhalation
(increases anteroposterior dimension of thorax).
• B. Scalene muscles:
• Origin= transverse processes of cervical
vertebrae to insertion on two uppermost ribs
• ACTION: supplementary m. of inhalation-raise
first two ribs.
• CLINICAL NOTE: excessive use of the neck
musculature is freq. in patients with chronic
lung disease. Pronounced use of upper thoracic
and neck muscular during inhalation is termed
clavicular breathing, and usually regarded as
inefficient and undesirable. May be used as
compensation in patients. with paralysis of
principle breathing muscles.
• 3. Abdominal muscles are flexors of the
vertebral column & enclose and lend support to
abdominal contents.
• RESPIRATORY FUNCTION = may limit the
depth of inspiration, and are active in forced
exhalation.
• A. External oblique: most superficial of
abdominal muscles
• Origin = exterior surfaces of ribs 5-12. Course
medially and downward. Insert on iliac crest.
• Largest and strongest of abdominal muscles.
• ACTION: compresses abdominal contents,
thus raises intra-abdominal & intrathoracic
pressure. Used for emesis, defecation, and
forced expiration.
• B. Internal oblique: lie just deep to external
oblique--form middle layer of abdominal
musculature. Course just opposite to external
oblique. Arise from iliac crest, spread over
lateral wall of abdomen, insert into linea (linea
= stripe or streak) alba (white) (fibrous band
extending from xiphoid process to pubic
symphysis).
• ACTION: compress abdominal contents,
assists in expelling abdominal contents and in
forced exhalation.
• C. Transversus Abdominis: deepest
abdominal m.--as name implies, course is
horizontal. Arise on inner surfaces of ribs 6 12, and from iliac crest, and inguinal (pertaining
to groin) ligament. Insert into abdominal
aponeurosis (broad sheet of connective tissue,
connecting m. to bone). ACTION: compresses
abdominal contents--may be most effective m.
for forced exhalation.
• D. Torso muscles (upper limb & back)