heart and circulatory system

8/7/2019 Heart and circulatory system

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Heart and Circulatory system

>Heart is a complex closed hydraulicsystem

>Heart weighs between 7 to 15 ounces>Little larger than the size of our fist


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L ocation of HeartHeart is located in between our lungs in the middle of our chest


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Functions of the circulatory system:

D istribute nutrients ,

Transport and exchange oxygen and carbon

dioxideRemove waste materials

D istribute secretions of endocrine glands,


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P revent excessive bleeding ,

P revent infection , and

Regulate body temperature .

>Heart is divided into two parts (Right and Left)

>Each part has two chambers called atriumand ventricle


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>The h eart is a funnel-shaped, hollow,muscular organ that is responsible for pumping blood to all parts of the body.


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he Heart wall consists of three layers

P ericardiumOuter layer of the Heart

Myocardiummiddle layer of the Heartmain muscle of the HeartMade up of short cylindrical fibres

EndocardiumInner layer of the Heart


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F unctions:

P ericardium----keeps the outer layer moist .P revents friction as the Heart beats.

Myocardium---Is automatic in action,contracting and relaxing rhythmicallythroughout lifeEndocardium---smooth lining of blood to flow


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Heart valves


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The tricuspid valve regulates blood flowbetween the right atrium and right ventricle.

The pulmonary valve controls blood flow fromthe right ventricle into the pulmonary arteries,which carry blood to your lungs to pick upoxygen.

The mitral valve lets oxygen-rich blood fromyour lungs pass from the left atrium into theleft ventricle.


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blood from the heart gets around

the body through blood vessels

There are 3 types of blood vessels

a. ARTERY

b. VEIN

c. CAPILLARY


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The ARTERY

thick muscle andelastic fibres

Arteries carry blood away from the heart.

the elastic fibres allow

the artery to stretchunder pressure

the thick muscle cancontract to push the

blood along.


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The VEINVeins carry blood towards from the heart.

thin muscle and

elastic fibres

veins have valveswhich act to stop the

blood from going inthe wrong direction.

body muscles surround the veinsso that when they contract tomove the body, they also squeezethe veins and push the blood alongthe vessel.


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The CAPILLARYCapillaries link Arteries with Veins

the wall of a capillaryis only one cell thick

they exchange materialsbetween the blood and

other body cells.

The exchange of materialsbetween the blood and thebody can only occur throughcapillaries.


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artery vein

capillariesbody cell

The CAPILLARYA collection of capillaries is known as a capillary bedcapillary bed .


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The Heart

Left Ventricle

Left A triumRightA trium

Right Ventricle

valve

Vein from Lungs

Artery to Head and BodyArtery to Lungs

Vein from Head and Body

valve


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How does the Heart work?

blood from thebody

blood fromthe lungs

The heart beat begins when the

heart muscles relax and blood

flows into the atria.

STEP ONE


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The atria then contract andthe valves open to allow blood

into the ventricles.


STEP TWO


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The valves close to stop blood

flowing backwards.

The ventricles contract forcing

the blood to leave the heart.

A t the same time, the atria are

relaxing and once again filling with

blood.

The cycle then repeats itself .

STEP THREE


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Lungs

Body cells

Our circulatory system is a double circulatory system.This means it has two parts parts.

the right side ofthe system

deals with

deoxygenatedblood.

the left side ofthe system

deals with

oxygenatedblood.


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lungs

h ead & arms

liver

digestive system

kidneys

legs

pulmonary artery

aorta

pulmonary vein

main vein

LeftRight

How does this system work?

Circulatory System


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P ulmonary circulation


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S ystemic circulation


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Coronary Circulation


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The heart muscle, like every other organ or tissue inyour body, needs oxygen-rich blood to survive.Blood is supplied to the heart by its own vascular

system, called coronary circulation.The aorta (the main blood supplier to the body)branches off into two main coronary blood vessels(also called arteries). These coronary arteriesbranch off into smaller arteries, which supply

oxygen-rich blood to the entire heart muscle.The right coronary artery supplies blood mainly tothe right side of the heart. The right side of the heartis smaller because it pumps blood only to the lungs.The left coronary artery, which branches into the left

anterior descending artery and the circumflex artery,supplies blood to the left side of the heart. The leftside of the heart is larger and more muscular because it pumps blood to the rest of the body.


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The Heart rate is partly controlled byautonomic nervous system and partly byhormone action

The condition of the cardiovascular system isexamined by haemodynamic measurementsElectrocardiography( Recording the electricalactivity of the heart muscle)

P honocardiography (listening to heartsounds)


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NasalCavity

Nose

Mouth

Bronchus

Bronchiole

Alveolus

Diaphragm

Throat

(pharynx)

Windpipe

(Trachea)Left lungs

Ribs


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D iagram of D iaphragm

JH


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D ia phra g m E x pe rim e nt

JH


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F un F acts

* At rest, the body takes in and breathes out about 10 liters of air eachminute.

* The right lung is slightly larger than the left.* The highest recorded "sneeze speed" is 165 km per hour.* The surface area of the lungs is roughly the same size as a tennis court.

* The capillaries in the lungs would extend 1,600 kilometers if placed endto end.

* We lose half a liter of water a day through breathing. This is the water vapor we see when we breathe onto glass.

* A person at rest usually breathes between 12 and 15 times a minute.* The breathing rate is faster in children and women than in men.


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N ervous S ystem

Is the Complex System in the bodyP erforms 3 CsControl

Communication network for the bodyCo-ordinates the functions of the variousorgans


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The central processing un it (CentralInformation P rocessor)

The brain is the control center of the body

It is about 2% of your body weig h t and uses

20% of your bodys oxygen


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P arts of the N ervous S ystem

Central Nervous System (CNS): brain andspinal cord

P eripheral Nervous System ( P NS):craniospinal nerves

Autonomic Nervous System (ANS): nervesthat control vital organs: heart, lungs, brain,etc.


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P arts of the Brain

D ivided into th ree parts

CerebrumCerebellumBrain Stem


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Brain


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CerebrumCerebrum

Cerebellum


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Cerebrum

Largest part of the brain

2 h emisp h eres- Right and Left

Connected by the Corpus CallosumRig h t side controls- left side

Left side controls right side of body


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Cerebral Cortex - The outermost layer of gray mattermaking up the superficial aspect of the cerebrum.


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G yri (ridge)

Fissure(deep groove)

Sulci(groove)

http://williamcalvin.com/BrainForAllSeasons/img/bonoboL H- humanL H- viaTWD.gif


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Cerebral Features:

Sulci Small grooves dividing the gyri Central Sulcus Divides the Frontal Lobe from the ParietalLobe

Fissures Deep grooves, generally dividing large

regions/lobes of the brain Longitudinal Fissure Divides the two Cerebral Hemispheres

Transverse Fissure Separates the Cerebrum from theCerebellum

Sylvian/Lateral Fissure Divides the Temporal Lobe from theFrontal and Parietal Lobes

Gyri Elevated ridges winding around the brain.


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4 lobes( 2 in Right Hemisphere and 2 inthe L eft Hemisphere)

F our sections -LOBES

1.FrontalLobe2. ParietalLobe

3.OccipitalLobe4.TemporalLobe


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F rontal lobe:>Intelligence>Constructiveimagination>thought

>largequantities of information canbe storedtemporarily


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Temporary lobe:>Hearing centre

>located just abovethe ear> N eurons respondto different

frequencies of sound input>long-termmemory

> Organization/Comprehension of language


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P arietal lobe:> S enses and integrates

sensation>The sensory input comesfrom legs, arms, hands,fingers, face and throat

> Awareness of body/ body parts in space and inrelation to each other>Motor-centre (body

movement


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Occipital lobe

>Its primary function is the

processing, integration,interpretation, etc. of VIS IO N and visual stimuli.

> This is the primary area of the brain responsible forsight -recognition of size,color, light, motion,

dimensions, etc.


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Primary VisualCortex

VisualAssociation Area

Modified from: http://www.bioon.com/book/biology/whole/image/1/1 -8 .tif.jpg


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Cerebellum:> S econd largest

locatedbel ow

thecerebrum at back of skull

>This part is responsible

for the bala nc e andm usc le coordination


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P ons

P ituitary gland

Hypothalamus

Cerebrum

Medulla oblongata Spinal cord

Cerebellum

P inealgland

Thalamus


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Brain S tem

The brain stem connects the spinal cord tothe centre of the brain just bellow the cerebralcortexEssential parts are:Medulla Ablongatathe ponsmidbrainD iencephalon


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Medulla Ablongata

Lowest section of Brain StemM edulla Oblongata Controls h eart

rate, breath

ing rate, and flow of blood t h roug h th e blood vessels.Respiratory Centre which controls the

ventilation of the lungs


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P ons

Located just above the medullaP rotruding in front of brain stemRelays signals between the cerebrum and the

cerebellumC ontrols muscles of the face.


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midbrain: contains auditory (hearing), visual(sight), and muscle control centers.D iencephalon

ThalamusHypothalamus

ThalamusAct as a relay station for sensory

pathways


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Hypothalamus

connects the endocrine and nervoussystems.controlsthe autonomic nervous systembody temperaturecarbohydrate and fat metabolismappetiteemotions


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Body Temperature

In man, the deep body temperature mayfluctuate 1 degree Centigrade in daily activitycycles

Lowest in the morning and reaches a peak inlate evening


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Heat Balance and Body Temperature

Heat is continually being produced in thebody as a by-product of metabolismHeat is also continually being lost to thesurroundingsWhen the rate of heat production is exactlyequal to the rate of heat lost = HEAT

BALANCE


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Relationship of Body Heat to Body Temperature

The temperature of an object is a measure of the kinetic activity of its molecules

this is proportional to the amount of heatstored in the object

body temperature is directly proportional tothe heat in the body


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Heat capacity or S pecific heat

defined as the ratio of heat supplied (or remove) to thecorresponding temperature rise (or decrease)

= ( kilocalories/kg)/ TBT increases 1 C for each

BT increases 1 degree Centigrade for each calorie of

heat stored per kg of body weight

specific heat of tissues is said to be 0.83 calorie/kg


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N ormal Body Temperature

Internal or Core Temperature ( D eep BodyTemperature)temperature of the interior of the body

the body strives for a rather precise regulation of thistemperaturevalue normally varying from the mean by not morethan 1 F

2/3 of the body mass is at the core temperaturewhich is usually represented by the rectaltemperature


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S urface temperature

temperature of the skin or tissue immediatelyunderlying the skinrises and falls with the temperature of thesurroundings1/3 of the body mass


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Average Body Temperature

used when one wishes to calculate the total

amount of heat stored in the body

= (0.33 x surface temp) + (0.67 x internaltemp)


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P hysiologicalF luctuations

D iurnal variation minimum in AM; peaklate afternoon35 0 C early morning, cold weather 36 0-37 0 C usual range of normal38 0 C emotion and moderate exercise39 0 C hard work, emotions40 0 C hard exercise


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43 C (109.4 F ) Normally D EATH or serious braindamage

42 C ( 107.6 F ) May turn pale or remain flushed andredMay become comatoseBe in severe delirium, vomiting andconvulsionBlood pressure may be high or lowHeart rate fast

41 C ( 105.8 F ) F ainting, vomiting, severe headache,dizziness, confusion, hallucinations,delirium and drowsiness can occur P alpitation and breathlessness may

also occur

40 C(104F ) -F ainting, dehydration, weakness,vomiting, headache , dizziness,confusion, hallucination, delirium, anddrowsiness

39 C(102.2 F ) -Severe sweating, flushed n very red.-F ast heart rate and breathlessness

38 C(100.4 F ) -Sweating, feeling uncomfortable,


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37 C (98 .6 F) Normal body temp.

36 C ( 96.8 F ) Moderate shivering35 C ( 95.0 F ) Hypothermia intense shivering,

grayness skin34 C (93.2 F ) Severe shivering, loss movement of

finger, blueness and confusion

33 C ( 91.4 F ) Moderate to severe confusion,sleepiness, depressed reflexes, slowheart beat, shivering may stop

32 C ( 89.6 F ) Hallucination, delirium, completeconfusion, extreme sleepiness(comatose), shivering is absent

31 C (87.8 F ) Comatose, rarely conscious. No or slight reflexes, very shallow breathing

and sloe heart rate28 C ( 82.4 F ) Severe heart rhythm likely may stop

anytime.

24-26 C ( 75.2-78.8 F ) D EATH usually occurs


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Thermoregulation

D ef : an ability of an organism to keep thebody temperature within certain boundaries

One aspect of homeostasis process

Most enzymes are very sensitive


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F EVER

A fever is defined as a temperature 1 or more above the

normal 98.6 degrees F ahrenheit ( F ) or 37 degrees

Celsius (C).

F ever is not a disease.

F ever helps the body fight infections by making the

body's defense systems work more efficiently.

Bacteria and viruses cannot live at higher temperatures

and are killed by fever.


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F actors that affect heat productionand heat loss

HEAT P RO DU CTIONBMR causes continual heat productionnormal young adult male ordinarily produces at least 40 cal of heat/hour/sq meter body surface area

this raises the BT about 2F

in one hour if no heat were lost in thebodyabdominal viscera, heart, brain generates 63% of total body

heatskeletal muscle 30% of totalMuscular exercise as much as 75% of total heat produced inthe muscles when all the muscles of the body are contracted atmaximal rate of activity, the metabolic rate can rise to 1500 to2000 above the basal level


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>facilitation of anterior motoneurons causing anincreased muscle tone

rise in overall metabolic rate 50-100%>if degree of facilitation reaches a critical level

shivering begins;>the rate of heat production rises to 200-300%

above normalmajor mode of acutely increasing heat

production


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Thyroxine effect on cells

has a direct effect on all cells of the body toincrease the local rate of metabolism,causing greater than normal quantities of

heat to be released in the body

an increase of 100% above normal


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S pecific dynamic action of food

this increases the heat production of thebody

at high environmental temperature, thespecific dynamic action of food increases theheat production and adds extra burden to the

heat loss mechanism


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Heat L oss

The various methods by which heat loss iseffected are:

radiationconductionconvectionevaporation

The amount of heat loss by each of thesedifferent mechanisms varies withatmospheric conditions


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Radiation

loss of heat in the form of infrared heatrays

(electromagnetic waves)

the body radiates heat rays in all directions,and heat rays are being radiated from thewalls of other objects toward the body

varies directly with the temperaturedifference between the temperature of thebody surface and the average temperature of the surroundings


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The surface of the human body isextremely absorbent for heat rays

Rate of infrared absorption isapproximately equal for human beings with

either white or colored skin

The human skin absorbs 97% of incident

radiation


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The energy from the sun is transmitted mainly in

the form of light rays rather than infrared rays35% of these waves are reflected from the white

skin but only a small amount from the dark skinIn sunlight, a dark skin does absorb more heat

than white skinThe radiation surface of the standing human being

is only about 85% of the total surface area, since

exposed surfaces do not lose heat to theenvironment by radiation


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F actors influencing heat loss through radiation Temperature of surrounding objects relative to

that of the skin Humidity of the atmosphereAir with a high water vapor content is more

opaque to radiant heat than dry air

Heat loss through radiation is slightly reducedwhen the relative humidity is high

Rate of loss is proportional to Ts Te Ts absolute temperature of the skin surface Te absolute temperature of objects in

surroundingenvironment


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Conduction

Heat transfer between surfaces in contact1. Conduction to objects represents only a small

% of the total heat loss from the body (3%)

2. Conduction to air represents a sizeableproportion of the bodys heat loss even under normal conditions (12%)

Self-limited unless the air moves so that new,unheated air is continually brought in contact withthe skin


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Convection

Movement of air The clothed body has a layer of warm moist air in contact with the

skinWhen the atmosphere is cooler, convection currents are set up

which mix the air lying against the skin with fresh air When the body is exposed to wind, the layer of air immediately

adjacent to the skin is replaced by new air much more rapidly thannormally, and heat loss by convection increased accordingly

The loss increasing with the square of the wind velocity up to 60miles per hour

A wind velocity beyond this exerts little or no further effect Once the wind has cooled the skin to the temp of the air itself, a

further increase in the rate of heat loss cannot occur regardless of thewind velocity


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Evaporation

1. Invincible water loss about 25% of basal heat loss isattributable to evaporation of water even without sweatingThrough skin about 2/3Through respiratory tract 1/3

Heat loss by evaporation (E) is generally calculated fromwater loss, which maybe determined from body weightchanges after correction for metabolic and other weightlossesE (watts) = (0.7 x gms of H2O evaporated)/time in hours

Where: 0.7 = latent heat of evaporation (evaporation of 1gm of H2O per hour requires 0.7 watts or 0.6 K cal)


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S weat glands

Innervated by cholinergic nerve fibersTubular structures consisting of 2 parts:

D eep coiled portion that secretes the sweatD

uct portion passing outward through thedermis of the skinThe secretory portion secretes a fluid called

precursion Active secretory product of the epithelial cells

lining the coiled portion of the sweat gland Elicited by Cholinergic sympathetic nerve fibers

ending on or near the gland


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S weat

A water solution of an osmolar concentration wellbelow that of plasma

The principal constituent is sodium chloride

There are traces of potassium, urea and lactate,no protein or glucoseWhen the rate of sweat secretion is very low, most

of the sodium and chloride is reabsorbed from the

precursor secretion so that the fluid lost to thesurface of the body contains almost none of theseions


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Muscular S ystem

Muscles are responsible for all types of bodymovement3 basic muscle types are found in the body

Skeletal muscleCardiac muscleSmooth muscle


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k l l l h


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S keletal Muscle Characteristics

Striatedhave visible bindingVoluntaryMost attach to bones by tendonCells are multinucleateCells surrounded & bundled by connective tissueF unctions of Skeletal Muscle

P roduce MovementMaintain postureStabilize jointsGenerate Heat

Sites of Muscle AttachmentBonesCartilageConnective tissue coverings

S h l Ch i i


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S mooth Muscle Characteristics

Has no striationsSpindle-shapedcellsSingle NucleusInvoluntaryno

conscious controlF ound mainly in thewalls of holloworgans

Ch i i f C di M l


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Characteristics of Cardiac Muscle

Has striationsU sually has a single nucleusJoined to another cardiac

muscle cellInvoluntaryF ound only in the heart

heart and circulatory system

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