Muscles

So exciting

Muscle Control

• Involuntary Muscle: not under conscious control

• Ex: heartbeat, digestion

• Voluntary Muscle: Under your control • Ex: walking, jumping, dancing…

Types of MusclesSmooth Locations:

Walls of hollow organs (Stomach, lungs etc.)Blood vessels EyesSkinGlands

Not striated Uses:

Food movement through digestive tractRegulation of blood vessel diameterPupil dilationEmptying of bladder

Cardiac Location:

Heart Striated Involuntary Uses:

Pumps bloodMajor source that moves blood

throughout the body

Skeletal Location:

Attached to bonesStriated

Uses:Voluntary and involuntary movements

Types of Muscles

Take NOTES!!

• http://www.youtube.com/watch?v=bwOE1MEginA

Anatomy of a Muscle Cell

• Take notes!!!

• http://www.youtube.com/watch?v=uY2ZOsCnXIA

Skeletal Muscle Contraction

Acetylcholine reaches the muscle cell

Na+ gates on muscle open

Muscle fires

Ca2+ enters the muscle cell cytoplasm

Ca2+ binds to troponin and tropomyosin

Troponin moves away from the actin

Myosin cross-bridges attach to actin

Cross-bridges pull the actin

Actin filaments slide past myosin

ATP attaches to myosin cross-bridges

Cross-bridges release

Cross-bridges reattach

Let’s see it in Action! Take notes.

• http://www.youtube.com/watch?v=e3Nq-P1ww5E

• http://www.youtube.com/watch?v=hqynCsign8E

The Heart <3

BLOOD AND THE HEART FUN FACTS ♦ An average adult human contains

about 5 liters (5.3qt) of blood. ♦ The blood makes up about onethirteenth

of the body’s weight. ♦ The adult heart weighs about 280 grams (10 oz.) ♦ At rest, the heart pumps out about 80

millimeters(2.6 oz) of blood with each beat.

♦ The heart beats, on average, 70 times eachminute at rest.

♦ This means all the blood is circulated (goesround the body once) in about one minute.

♦ During strenuous exercise the heart can pumpsix to eight times the amount of blood that itpumps at rest.

Superior vena cava andinferior vena cava – bringdeoxygenated blood toright atrium

Pulmonary artery – takesblood away from rightventricle to the lungs forO2

Pulmonary veins – bring oxygenated bloodfrom lungs to left atrium

Aorta – takes blood away from left ventricle torest of the body

Chambers and Valves• SEPTUM divides into R and L halves• Upper chambers – RIGHT ATRIUM and LEFT ATRIUM

• Lower chambers – RIGHT VENTRICLE and LEFT VENTRICLE

• Four heart valves permit flow of blood in one direction

TRICUSPID VALVE – between right atrium andright ventricleBICUSPID (MITRAL) VALVE – between left atriumand left ventricleSemilunar valves are located where blood leavesthe heart - PULMONARY SEMILUNAR VALVEand AORTIC SEMILUNAR VALVE

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Overview • The right side receives

oxygen-poor blood from the body and tissues and then pumps it to the lungs to pick up oxygen and dispel carbon dioxide

• Its left side receives oxygenated blood returning from the lungs and pumps this blood throughout the body to supply oxygen and nutrients to the body tissues

The heart=a muscular double pump with 2 functions

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• Two circulations– Systemic circuit: blood vessels that transport

blood to and from all the body tissues

– Pulmonary circuit: blood vessels that carry blood to and from the lungs

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Chambers of the heartsides are labeled in reference to the patient facing you

• Two atria– Right atrium– Left atrium

• Two ventricles – Right ventricle– Left ventricle

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Valvesthree: tricuspidone: bicuspid

• “Tricuspid” valve– RA to RV

• Pulmonary valve– RV to pulmonary trunk (branches R and L)

• Bicuspid valve (the bicuspid one)– LA to LV

• Aortic valve– LV to aorta

(cusp means flap)

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Function of AV valves

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Function of semilunar valves(Aortic and pulmonic valves)

Meet the Heart

• http://www.youtube.com/watch?v=Vi1JK6IYVt8

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Pattern of flow(simple to more detailed)

• Body• RA• RV• Lungs• LA• LV• Boby

Body to right heart to lungs to left heart to body

Body, then via vena cavas to RA, to RV via tricuspid valve, then to lungs through pulmonary semilunar valve and via pulmonary arteries, then to LA via pulmonary veins, to LV via bicuspid, then to body via aortic semilunar valve and the aorta

LEARN THIS

Cardiac CycleBlood enters the atria through the vena cava (R) and the Pulmonary vein (L)

↓Atria will contract

↓Blood is pushed through the AV valves into the ventricles

↓Ventricles contract and AV valves close

↓Blood is pushed though the pulmonary and aortic semilunar valves into the

pulmonary trunk and the aorta↓

Ventricles relax and valves close

Cardiac Cycle Tutorial

• http://faculty.alverno.edu/bowneps/cardiaccycle/cardiaccycle1map.htm

PHYSIOLOGY OF THE HEARTThe heart is a double pump. When the heartbeats…Right HeartDeoxygenated blood flows into heart from venaCava ---right atrium ---tricuspid valve--- rightventricle --pulmonary semilunar valve---pulmonary artery ---lungs (for oxygen)Left HeartOxygenated blood flows from lungs via pulmonaryVeins--- left atrium--- bicuspid valve--- left ventricle--- aortic semilunar valve--- aorta --- general circulation (to deliver oxygen)

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Electrical conduction system:

(Explanation in next slides)

specialized cardiac muscle cells that carry impulses throughout the heart musculature, signaling the chambers to contract in the proper sequence

Control of Heart ContractionsSA (sinoatrial) NODE = PACEMAKER• Located in right atrium• SA node sends out electrical impulse• Impulse spreads over atria, making themcontract• Travels to AV Node

AV (atrioventricular) NODE• Conducting cell group between atria andventricle• Carries impulse to bundle of His

BUNDLE OF HIS• Conducting fibers in septum• Divides into R and L branches to network ofbranches in ventricles (Purkinje fibers)

PURKINJE FIBERS• Impulse shoots along Purkinje fibers causingventricles to contract

Flow Through the Heart

• http://www.youtube.com/watch?v=7XaftdE_h60

SA NodeSinalarterial node “Pacemaker”

AV NodeAtrioventricular nodeAllows impulse to crossinto ventricles

Bundle of HisBundle Branches

Purkinje Fibers

Heart Contraction

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Conduction system

• SA node (sinoatrial) – In wall of RA– Sets basic rate: 70-80– Is the normal pacemaker

• Impulse from SA to atria• Impulse also to AV node via internodal

pathway• AV node – In interatrial septum

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Conduction continued

• SA node through AV bundle (bundle of His)– Into interventricular septum– Divides

R and L bundle branches

become subendocardialbranches (“Purkinjefibers”)

• Contraction beginsat apex

Heart Contraction Flow ChartSA Node fires

↓Impulse spreads across atria

↓Atria contract (lub)

↓Blood is pumped to the ventricles

↓AV Node receives impulse from SA Node

↓Impulse passes through bundle of His

↓Impulse passes through Purkinje fibers

↓Ventricles contract (dub)

↓Blood is pumped into the lungs and out to the body

• Watch- Electrical Changes in the Heart

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EKG→ measures heart electricity

P Wave→ Atria contract & Depolarize PQ Interval→ Impulse is passing through the

bundle of His to the Purkinje fibersQRS Wave→ Ventricles depolarize and contractT Wave→ Ventricles repolarize