Exam 2

Endocrine Glands

release hormones directly into blood

Hormones

alter activity of tissues that possess receptors that hormones bind to

Plasma Hormone Concentration

determines magnitude of effect of hormones at tissue level

Hormone Receptor Integration

\-stimulate DNA directly to increase protein synthesis

\-activating second messengers (Cyclic AMP & Ca++)

Hypothalamus

\-controls activity of anterior & posterior pituitary glands

\-influenced by positive & negative input

Anterior Pituitary Gland

\-secretes growth hormone

Growth Hormone

\-stimulates protein synthesis & long bone growth

\-increases during exercise

-maintenance of blood glucose by increasing gluconeogenesis

Posterior Pituitary Gland

\-secretes ADH

\-reduces water loss from body to maintain plasma volume

What happens to plasma ADH concentration during exercise?

it increases

Thyroid Gland

\-secretes T3 & T4

\-increases during exercise

\-glucose maintenance

Adrenal Medulla

\-secretes catacholamines (epinephrine & norepinephrine)

\-increases during exercise

\-glucose maintenance

Adrenal Cortex

\-secretes aldosterone

\-increases during exercise

\-plasma volume maintenance

Adrenal Cortex

\-secretes cortisol

\-increases during exercise

\-glucose maintenance

Pancreas

\-secretes insulin & glucagon

\-blood glucose maintenance

Insulin

\-storage of glucose

\-down during exercise

Glucagon

\-mobilization of glucose

\-up during exercise

FFA mobilization during heavy exercise

\-FFA mobilization decreases during heavy exercise

Functions of Skeletal Muscle

\-force production for locomotion & breathing

\-force production for postural support

\-heat production during cold stress

Connective Tissue Covering Skeletal Muscle

\-epimysium

\-perimysium

\-endomysium

Epimysium

surrounds entire muscle

Perimysium

surrounds bundles of muscle fibers (fascicles)

Endomysium

surrounds individual muscle fibers

Tendon

connect muscle to bone

Fascicle

bundle of muscle/nerve fibers

Sarcolemma

thin cell membrane surrounding a striated muscle fiber

Myofibrils

\-bundles of interconnected protein filaments of striated muscles

\-thick & thin filaments

Sarcoplasmic Reticulum

\-membrane-bound structure within muscle cells

\-storage of calcium ions

Sarcomere

\-functional unit of striated muscle (most basic unit)

\-repeating unit between 2 z-lines

\-arrangement of thick & thin filaments

Z Line

\-line that anchors actin myofilaments

\-found between two sarcomeres

Transverse Tubule (T Tubule)

\-transmit muscle impulses into cell interior

\-anchor z-lines around the myofilaments

Terminal Cisternae

\-store calcium & release it when action potential comes down T tubules

\-ensure rapid calcium delivery

\-found on either side of T tubule

Actin & Myosin Relationship

\-thick myosin filaments

\-thin actin filaments

\-work together to generate muscle contractions & movement

\-myosin converts chemical energy released from ATP into mechanical energy

\-mechanical energy used to pull actin filaments, causing muscle contraction

Properties of Muscle Fiber Types

\-biochemical properties

\-contractile properties

Biochemical Properties

\-oxidative capacity

\-type of ATPase

Contractile Properties

\-maximal force production

\-speed of contraction

\-muscle fiber efficiency

Individual Fiber Types

\-fast fibers

\-slow fibers

\-type IIa fibers

Fast Fibers (type IIx)

\-low # of mitochondria

\-low resistance to fatigue

\-anaerobic

\-highest ATPase

\-highest Vmax

\-high FORCE

\-low capillaries

\-80-90m/s action potential speed

Slow Fibers (type I)

\-high # of mitochondria

\-high resistance to fatigue

\-aerobic

\-low ATPase

\-low Vmax

\-moderate FORCE

\-high capillaries

\-60-70 m/s action potential speed

Type IIa Fibers (intermediate)

\-high/mod # of mitochondria

\-high/mod resistance to fatigue

\-combination

\-high ATPase

\-intermediate Vmax

\-high FORCE

\-low capillaries

Can fiber types be altered by training?

no, but you can shift them towards more oxidative properties

Types of Muscle Contraction

\-isometric

\-isotonic (dynamic)

\-isokinetic

Isometric

\-muscle exerts force w/o changing length

\-pulling against immovable object

\-postural muscles

Isotonic (dynamic)

\-concentric (muscle shortens during force production)

\-eccentric (muscle produces force but length increases)

Isokinetic

speed of movement remains constant but resistance varies

Force Regulation in Muscle

\-types & number of motor units recruited

-more motor units = greater force

- fast motor units = greater force

-increasing stimulus strength recruits more & faster/stronger motor units

\-initial muscle length

-”ideal” length for force generation

\-frequency of stimulation

-simple twitch, summation, tetanus

Heart

pumps blood

Arteries & Arterioles

carry blood away from the heart

Capillaries

exchange of nutrients w/ tissues

Veins & Venules

carry blood toward the heart

Aorta

main artery responsible for transporting oxygenated blood out of the heart & to rest of the body

Left Atrium

\-left posterior side of heart

\-holds blood returning from lungs

\-acts as pump to transport blood to other areas of the heart

Right Atrium

\-blood circulation

\-collects deoxygenated blood & directs it on pathway to get oxygen from the lungs

Right Ventricle

takes blood that doesn’t have oxygen & pumps it to the lungs through pulmonary valve

Left Ventricle

\-bottom left portion of heart

\-blood pumped from here out through aortic valve into arch and to res of body

\-pumps oxygenated blood to tissues all over the body

Interventricular Septum

\-triangular wall of cardiac tissue that separates both ventricles

\-receives blood supply from left and right coronary artery

Systemic Circuit

\-left side of heart

\-pumps oxygenated blood to whole body via arteries

\-returns deoxygenated blood to right heart via veins

Pulmonary Circuit

\-right side of heart

\-pumps deoxygenated blood to lungs via pulmonary arteries

\-returns oxygenated blood to left heart via pulmonary veins\`

Coronary Vessels

\-supplying blood to the heart

Fibrous Pericardium

\-keeps heart in stable location

\-facilitates heart movements

\-separates heart from lungs

Serous Pericardium

\-mechanical protection for heart & big vessels

\-lubricant reduces friction between heart & surrounding structures

Pericardial Cavity

tough sac that encloses the heart

Systole

contraction phase

Diastole

relaxation phase

Pulse Pressure

difference between systolic & diastolic (systolic - diastolic)

Mean Arterial Pressure (MAP)

average pressure in arteries (MAP = diastolic + 1/3(pulse pressure))

What are the factors that influence arterial blood pressure?

\-blood volume increases

\-heart rate increases

\-stroke volume increases

\-blood viscosity increases

\-peripheral resistance increases

Sinoatrial Node (SA Node)

generates electrical current

Atrioventricular Node (AV Node)

electrical relay station between upper & lower chambers of the heart

Atrioventricular Bundle (Bundle of His)

transmits electrical impulses from AV node to Purkinje fibers

Intercalated Discs

\-cardiac cell-to-cell communication

\-coordinate muscle contraction

\-maintenance of circulation

Purkinje Fibers (Conduction Myofibers)

\-specialized nerve cells

\-send electrical signals to right & left ventricles

Cardiac Output

amount of blood pumped by the heart each minute

Q = HR x SV

\-heart rate = number of beats/minute

\-stroke volume = amount of blood ejected/beat

Carotid Sinus

\-reflex area of carotid artery

\-consists of baroreceptors that monitor BP

Baroreceptors

\-monitor BP

Common Carotid Artery

\-source of oxygenated blood to head & neck

Parasympathetic Vagus Nerve

\-calms body after stressful situation

Sympathetic Cardiac Nerve

\-rest and digest

\-sends messages regarding HR, digestion, respiratory, or certain reflexes

End-Diastolic Volume (EDV)\`

volume of blood in ventricles at the end of diastole (“preload”)

\-venous return

Average Aortic Blood Pressure

pressure the heart must pump against to eject blood (“afterload”)

Strength of the Ventricular Contraction

contractility

Neuromuscular Junction

\-site where motor neuron & muscle cell (fiber) meet

\-allows motor neuron to transmit a signal to the muscle fiber, causing a contraction

Muscular Contraction

\-complex process involving number of cellular proteins & energy production systems

\-final result is sliding of actin over myosin, which causes muscle (myofibrils) to shorten & develop tension

Muscle Fibers per Nerve

1. Fine work - eyes - 1 nerve/10 muscle fibers
2. Medium - hands - 1 nerve/500 muscle fibers
3. Gross - legs, arms - 1 nerve/2000-3000 fibers

Force Regulation in Muscle

\-types & # of motor units recruited

\-increased motor units = increased force

\-fast motor units = increased force

Golgi Tendon Organ (GTO)

\-monitor tension developed in muscle

\-prevents damage during excessive force generation (stim results in reflex relaxation of muscle)

Function of Arteries & Arterioles

carry blood away from heart

Function of Capillaries

exchange nutrients w/ tissues

Function of Veins & Venules

carry blood to heart

Myocardium

\

1. epicardium
2. myocardium
3. endocardium

Pulse Pressure

pulse pressure = systolic - diastolic

MAP (mean arterial pressure)

MAP = diastolic + 1/3(pulse pressure)

Electrical Activity of Heart

\-contraction of heart depends on electrical stim of myocardium

\-impulse initiated in right atrium & spreads throughout heart

\-recorded on ECG

Electrocardiogram

1. P-wave


1. atrial depolarization
2. QRS complex


1. ventricular depolarization
3. T-wave


1. ventricular repolarization

Cardiac Output

-amount of blood pumped by heart/min

\-product of HR & stroke volume (Q = HR x SV)

Regulation of Stroke Volume

\-end-diastolic volume

\-avg. aortic BP

\-strength of ventricular contraction

End-Diastolic Volume (EDV)

volume of blood in ventricles at end of diastolic (preload)

\-Frank-Starling Mechanism

\-affected by venous return

What is Venous Return?

volume of blood in ventricles at end of diastolic (EDV)

Average Aortic BP

pressure the heart must pump against to eject blood (afterload)

What is venous return affected by?

\-venoconstriction

\-skeletal muscle pump

\-respiratory pump

Frank-Starling Mechanism

greater preload results in stretch of ventricles & more forceful contraction