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BY 409 Mammalian Physiology Test 3
Test
147
Biology
11/04/2009

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Cards

Term
TF Muscles are the smallest group of organs in the body
Definition

False

Muscles are the largest group of tissues in the body

Term
TF Cardiac muscle is 40% of body (by weight)
Definition

False

Skeletal muscle is 40% of body by wt.

Term
TF Smooth muscle and Cardiac muscle make up 10% body by wt
Definition
True
Term
TF Skeletal muscles are involuntary muscles
Definition

False

They are voluntary muscles that you consciously control

Term
What do skeletal muscles include? (give examples)
Definition
diaphragm, tongue, and muscles that move the eye
Term
_____________ are attached to the skeleton and allow for mvmt of the _________
Definition

1. skeletal muscles

2. bones

Term
What is the skeletal muscle made up of?
Definition
bundles of muscle fibers
Term
muscle fiber = ?
Definition
individual muscle cells
Term
What are the 6 characteristics of muscle fibers?
Definition

1. the muscle fiber is a Large cell

2. they are 10-100 micrometers in diameter

3. they are very long and extend the length of hte muscle

4. they are formed by the fusion of smaller cells during embryonic dev.

5. they are multinucleate

6. A single motor neuron innervates one muscle fiber

Term
TF Myofibrils are made up of muscle fibers
Definition

False

Muscle fibers are made up of myofibrils

 

* muscle--muscle fiber--myofibril**

The muscle is made up of muscle fiber (muscle cell) and muscle fiber is made up of myofibrils

Term
TF muscle fibers are made up of myofibrils
Definition
True
Term
Myofibrils make up ___ percent of muscle fiber by volume
Definition
80%
Term
What are myofibrils composed of?
Definition
microfilaments (ex: actin and myosin)
Term
Describe what myofibrils are
Definition
they are special contractile units found within the muscle fiber (ie muscle cell)
Term
TF Smooth muscle is striated
Definition

False

Skeletal muscle is striated

Term
What causes the striations in skeletal muscle?
Definition
the alternating light and dark bands
Term
TF the alternating dark and light bands are made up of actin and myosin
Definition
True
Term

1.Dark band =

2. Light band =

Definition

1. myosin and overlap of myosin and actin

 

2. actin and Z line

Term
What is the Z line?
Definition

a. it is the attachment site for actin

b. made up of filamentous proteins

Term
TF Sarcomere is the functional unit of a Z line
Definition

False

Sacomere is the functional unit of the myofibril

Term
Where is the sarcomere located?
Definition
Between two Z lines
Term
What causes the striations of skeletal muscle?
Definition
Z line of one myofibril is lined up with Z line of another myofibril, thus causing striations in skeletal muscle
Term
What are the two molecular structures found within teh sarcomere?
Definition
Myosin and Actin
Term

TF thick filament = actin and

thin filament = myosin

Definition

False

thick filament = myosin

thin filament = actin

Term

Myosin has __ subunits

Each subunit composes of a_______________ head

 

Definition

1. 2

 

2. golfclub-shaped

Term
what does the golf-club shaped head function as?
Definition
it funcs. as a crossbridge btwn myosin and actin
Term
TF the myosin head has 3 active sites
Definition

False

It only has 2 active sites

Term
What are the two active sites of the myosin head?
Definition

1. actin binding site: binds actin

 

2. myosin ATPase binding site: binds and cleaves ATP

Term
TF Thin filaments only contain actin
Definition

False

Thin filament includes:

actin

tropomyosin

troponin

Term
TF Actin molecules are made up of globular proteins
Definition
True
Term
The actin helix is made up of:
Definition

a. actin molecules (which are globular proteins)

b. binding site for myosin head

Term
TF Tropomyosin is a thick filament
Definition

False

it is a thin filament

Term

What are the is the func. of tropomyosin?

 

Definition

a. acts as a regulatory protein for muscle contraction

b. covers binding sites on actin

Term
TF tropomyosin is a thread-like protein that lies end to end
Definition
True
Term
TF Tropomyosin wraps around Actin and troponin
Definition

False

It only wraps around the actin helix

Term
TF tropomyosin and troponin act as regulatory proteins for muscle contraction
Definition
True
Term
What is Troponin made up of?
Definition
3 polypeptide subunits
Term
What are the 3 polypeptide subunits troponin is made up of?
Definition

1. Troponin T

2. Troponin I

3. Troponin C

Term
TF Troponin T binds to actin
Definition

False

Troponin T binds to tropomyosin

Term
TF troponin I binds to actin
Definition
True
Term
Troponin C binds to______
Definition
Ca2++
Term
What is the func. of the troponin-tropomyosin complex
Definition
both proteins join toge. to make a complex which covers the actin binding sites
Term
TF during muscle contraction the level of Ca2++ is low
Definition

False

During muscle relaxation Ca2++ is low

 

During muscle contraction Ca2++ is high

Term
TF When Troponin C binds to Ca2++ the myosin head tilts causing a power stroke
Definition

False

When troponin C binds to calcium, this stimulates the T2 complex to undergo a conformational changes which uncovers the actin binding site

Term
Definition
Term
TF When ATP is bound to the myosin head, it causes it to tilt forward
Definition

False

When ATP is bound to myosin head, it causes the head to detach from the actin binding site

Term
Describe the steps in muscle contraction
Definition

1. intracellular Ca2++ is high

2. Troponin C binds to Ca2++

3. This causes T2 complex to undergo a conformational change which will uncover the actin binding site

4. myosin head will now bind to the actin binding site

5.This will trigger a conformational change in myosin causing the head to tilt forward (ie power stroke)

6. Tilting of the head releases ADP

7. ATP will now bind to the myosin head

8. It will cause the myosin head to detach from the actin binding site

9. ATP will then be cleaved to ADP by ATpase of the myosin, this will cause the myosin head to return to its orginal (nontilted) form

10. When ATP is cleaved energy is put back into the system which can be used for the next power stroke

Term
TF muscle contraction can occur if Na+ is present
Definition

False

it can occur if only Ca2++ is present

Term
TF muscle contraction is known as the "walk along" theory
Definition
True
Term
What is rigor mortis known as?
Definition
Stiffness of the muscles
Term
When does it occur?
Definition
3-12 hrs. after death
Term
Definition
Term
TF During rigor mortis, new ATP is used and new ATP is made
Definition

False

During rigor mortis, existing ATP is used and NOOO new ATP is made

Term
What actually causes the muscle to become stiff?
Definition
Since no new ATP is made, the pool of ATP is exhausted, so noo new ATP will bind to the myosin head, myosin head will notttt detach from the actin binding site, the muscle will not relax, thus causing the muscle to become STIFF
Term
TF one Sensory neuron innervates many muscle fibers
Definition

False

Each muscle fiber is innervated by a single motor neuron

Term
how does a motor neuron innervate a muscle fiber?
Definition
via the neuromuscular junc.
Term

TF The neuromuscular junc. is made up of

1. axon terminal of motor neuron

2. motor-end plate of muscle

Definition
True
Term
What happens when an AP passes thru the motor neuron?
Definition
an AP thru the motor neuron causes Ca2++ influx into the axon terminal
Term
TF Ca2++ influx in the axon terminal causes Ach to be releaseed
Definition
True
Term
TF Ach is released thru the synaptic cleft and attaches to Ach receptors on teh motor end plate of the muscle
Definition

False

When  Ach is released and it travels thru the synaptic cleft it attaches to  nicotinic receptors

Term
When Ach binds to nicotinic receptors, what is open and what do you have a increase/decrease in?
Definition
when Ach is bound to nicotinic receptors, ligand gated channels are open and large amounts of Na and small amounts of K+ pass thru the membrane
Term
When Na and K pass thru the membrane what do they generate?
Definition
end-plate potential
Term

TF The end-plate potential is an AP

 

Definition

False

it is a graded potential

Term
TF an AP doesnt occur in the end plate region
Definition
True
Term
TF, even though an AP doesnt occur in the end-plate region, it can initate an AP in adjacent areas of the membrane
Definition
True
Term
When an AP is initiated in adjacent areas of the membrane, what occurs?
Definition
When an AP is initiated in adjacent areas of the membrane, it can open up voltage-gated ion channels
Term
TF Ach release stimulates end plate pot.
Definition
True
Term
What terminates the stimulatory effect of Ach?
Definition

Acholinenesterase

or cholinesterase

Term
TF the drug that blocks the release of Ach is known as botulinum toxin
Definition
True
Term
What produces the b.toxin
Definition
bacterium called C.botulinum
Term
What is botulism?
Definition
refers to food poisoning caused by the toxin
Term

TF b.toxin isnt a toxin substance

Definition

False

it is a very toxic substance

less than 1 millionth of a gram can be lethal!!

Term
What are the two things b.toxin causes?
Definition

1. paralyzes the muscle, including the diaphragm

2. causes respiratory failure

Term
TF b.toxin was the first biological toxin to be licensed for therapeutic use
Definition
True
Term
What are some of the uses of b.toxin?
Definition

1. used in a dilute form to relax hyperexcitable muscles (it was injected into the muscle)

2. used cosmetically to get rid of deep wrinkles, aka botox injections

3. used for specific voice disorders

4. can be used to prevent excessive sweating

5. can be used to treat migraines

 

Term
TF the drug that causes the release of Ach is known as cholinesterase
Definition

False

the drug that increases the release of Ach is knwn as black widow spider venom

Term
Definition
Term
TF black widow spider venom has the same effect as b. toxin
Definition

False

they have opp. effects

 

a. bws venom causes an explosive release of Ach

b. b. toxin block the release of Ach

Term
When a lot of Ach is released due to bws venom, what occurs
Definition
it causes an excessive and prolonged stimulation of muscles, results in muscle spasms, which result in muscle fatigue
Term
TF Death from black widow spider is very prominent
Definition

False

death from the venom is very rare!!

Term
TF when Ach nicotinic receptors are blocked, the neuromuscular junc. is also blocked
Definition
True
Term
What are the two drugs that attach to and block the nicotinic receptors?
Definition

1. curare

2. alpha-bungaro toxin

Term
_________________ is found in plant extracts and blocks _____________ receptors
Definition

curare

nicotinic

Term
What is alpha-bungarotoxin found in?
Definition
venom of poisonous snakes
Term

 TF most snake venom contains toxins that block nicotinic receptors, thus blocking release of Ach

Definition
True
Term
In  response to end plate potential, where is the AP produced?
Definition
AP is produced in adjacent motor end regions
Term
TF an AP is conducted along the surface of a muscle fiber
Definition
True
Term
TF b/c the muscle fiber has a large diameter, the AP conducted along the surface doesnt have an effect deep in the fiber
Definition
TRue!!!
Term
Break, happy time
Definition
:-D
Term
TF T-tubules carry AP deep into the muscle fiber
Definition
True
Term

What are T-tubules?

 

Definition

a. Transverse tubules

 

b. extention of the membrane and they run perpendicular from teh surface

 

c. tubules that carry AP deep within the muscle fiber

Term
TF the T-tubules carry an AP that can stimulate the sarcoplasmic reticulum
Definition
True
Term
TF the SR is a specialized type of ER
Definition
True
Term
Describe the SR
Definition
it is an elaborate meshwork of tubules that surrounds the myofibrils
Term

TF SR is a specialized organelle for the storage of intracellular K+

 

Definition

False,

it stores Ca2++

Term
TF Ca2++ pumps continously pump Ca2++ out on the SR membrane
Definition

False

they pump Ca2++ IN

Term
__________ in the T-tubules causes release of Ca2++
Definition
AP
Term
When calcium is released what does it bind to?
Definition
Troponin C
Term
Upon binding to troponin C, Ca2++ initiates____________
Definition
muscle contraction
Term
TF when a muscle is at rest, there is no AP
Definition
True
Term
When the muscle is at rest, what happens to Ca2++
Definition
it is actively pumped back into the SR
Term
TF during muscle relaxation, Ca2++ in ICF is low
Definition
True
Term
Due to low Ca2++ in the ICF, what happens?
Definition
myosin head cannot bind to actin, thus causing the muscle to relax
Term
Where is smooth muscle found?
Definition
walls of the viscera
Term
TF smooth muscles can be found in the digestive tracct
Definition

True

Smooth muscle is found in the digestive tract, blood vessels, ureters and uterus

Term
TF smooth muscle forms the ciliary and iris muscles of the eye, and piloerector muscles
Definition
True
Term
TF smooth muscle has larger muscle fibers than skeletal muscle
Definition

False

Smooth muscle has smaller muscle fibers than skeletal muscle

2-5um diameter

20-500um in length

Term
TF Smooth muscle doesnt contain myofibrils
Definition
True
Term
What are some characteristics of smooth muscle?
Definition

- has actin and myosin

-doesnt have myofibrils

no striations

no t-tubules

-poorly developed SR

- actin is bound to proteins callled "dense bodies" instead of z line

 

Term
TF Smooth muscle is better for fast, powerful contractions of the muscle
Definition

False

b/c smooth muscle has very little characteristics, it is best used for slow, prolonged muscle contraction

 

Skeletal muscle is used for the fast and powerful muscle contraction

Term
TF in smooth muscles Ca2++ enters from the SR
Definition

False

Ca 2++ in smooth muscle enters from ECF

Ca 2++ in skeletal muscle enters from the SR

Term
TF an AP running along the smooth muscle cell membrance causes an increase in Ca2++
Definition
True
Term
Once Ca2++ is released into the ICF, what does it bind to?
Definition
It binds to calcium receptors call calmodulin
Term
Once Ca2++ binds to calmodulin, what occurs next?
Definition

They form a complex which activates "myosin kinase"

 

myosin kinase activates myosin head

Term
TF the myosin head will bind to actin causing a power stroke/muscle contraction
Definition
True
Term
Definition
Term
Describe the steps of SMOOTH muscle contraction
Definition

1. An AP runs down the smooth muscle membrane increasing level of Ca2++

2. Ca2++ enters the ICF from ECF

3. Ca2++ binds to calmodulin

4. Ca2++ and calmodulin form a complex which activates "myosin kinase"

5. myosin kinase activates myosin

6. myosin binds to actin, thus causing a power stroke

Term

TF Smooth muscle can occur with the presence of Na+

 

Definition

False

it occurs with the presence of Ca2++

Term
TF smooth muscle uses less energy than skeletal muscle during contraction
Definition
TRue
Term
TF smooth muscle contraction is known as slow and economical
Definition
TRue!!
Term
Which muscle forms the electrical synctium
Definition
Smooth muscle
Term
What is electrical synctium??
Definition

1. it is when cell membranes of adjacent cells are joined by gap juncs. which allow for flow of ions btwn cells

 

2. it is where depolarization in one cell causes depolarization in an adjacent cell

Term
TF smooth muscle in the digestive tract is autorhythmic
Definition
True
Term
Lecture 16
Definition
Lecture 16
Term
TF Cardiac muscles have intercalated discs, used to connect indv. cells
Definition
True
Term
What are intercalated discs?
Definition

cell membranes that connect two indv. cells toge.

 

they contain:

1. gap juncs.

2. desmosomes

Term
TF Gap junctions mechanically attach two cells toge.
Definition

False

Desmosomes mechanically connect two cells toge.

 

Gap junc. connect to cells toge. for ion flow

Term
TF Smooth muscle AP have a longer duration (250msec) than Cardiac muscle
Definition

False

Cardiac muscles have LONGER duration AP

Term
TF Cardiac muscle AP have a Plateau phase in which, theres a large influx of Na+
Definition

False

Cardiac muscle DO have a Plateau phase, but in  the plateau phase you have an increased PERMEABILITY of Ca2++ due to the slow opening and closing of Ca2++ channels

Term
What causes the depolarization phase in cardiac muscles?
Definition
rapid opening of Na+ channels and rapid influx of Na+
Term
TF during the plateau phase there is high permeability of Ca2++ and K+ and a low permeability of Na+
Definition

False

high permeability = Ca2++

low permeability = K+ and Na+

Term
TF the purpose of having a steady flow of Ca2++ into the ECF is to maintain a (-) potential of the ECF
Definition

False!!

Steady flow of Ca2++ occurs into ICF

maintains a (+) potential in ICF

Term
TF repolarization phase is knwn as the falling phase
Definition
True
Term
TF during repolarization K+ channels open and Ca2++ channels close
Definition
True!!
Term
TF we have a prolonged AP so that it allows for a prolonged muscle contraction and prolonged absolute refractory period
Definition

False

prolonged AP =

1. prolonged muscle contraction

2. prolonged REFRACTORY period

Term
A prolonged muscle contraction and refractory period allow for what 2 things?
Definition

1. prevents rapid restimulation of the heart muscle

2. allows for the efficient pumping of the blood and filling of hte heart

Term
TF the cardiac cycle is the period from the beginning of one heartbeat to the end of one heartbeat
Definition

False

its the period from the beginning of one heartbeat to the beginning of another heartbeat

 

Term
TF Diastole is the contraction period of the cardiac cycle
Definition

False

It is the relaxation phase

Term
TF Normal systolic BP is 80mm of Hg
Definition

False

Normal systolic BP = 120mm of Hg

Normal diastolic BP = 80mm of Hg

Term
What happens during the diastole phase?
Definition

heart is relaxed and filling with blood

BP is maintained by the elasticity of major arteries

 

 

Term
TF systole phase is the contraction phase of the cardiac cycle
Definition
True
Term
What are the two basic types of electrically responsive tissues in the heart?
Definition

1. contractile fibers

2. autorhythimic tissue

Term
TF contractile fibers cannot initiate their own AP
Definition
True
Term
TF autorhythmic tissue is responsible for the initiation and conduction of AP in the heart, leading to heart contraction
Definition
True!!
Term
In autorhythmic tissue, you have a sponataneous __________________ due to a leak in ____________
Definition

depolarization

Na+ channels

Term
What are the depolarization rates for the different types of autorhythmic tissues?
Definition

SA node = 70-80bpm

AV node = 40-60bpm

AV bundle = 15-40bpm

Purkinje fibers = 15-40bpm

Term
Definition