Lektion 8 - skeleton, muscles and tendons Flashcards by Linnéa Hallberg

What are seven functions of muscles?

1) Respiration
2) Circulation
3) Digestion
4) Empty contents from the body
5) Locomotion
6) Reproduction
7) Produce heat and sound

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What are the three types of cytoskeleton?

1) Actin filaments
2) Microtubule
3) Intermediate filaments

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What is a cytoskeleton?

A protein based intracellular network

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What are motor proteins?

Enzymes that use energy from ATP to move

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How does the cytoskeleton and the motor proteins work togheter?

The motor proteins walk on filaments or microtubules

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Name three important types of motor proteins

1) Dyneins
2) Kinesins
3) Myosins

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What is the function of dyneins?

They walk in microtubule in cilia and flagella

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What is the function of kinesins?

They walk on microtubule in vesicular transport (subcellular movement)

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What is the function of myosins?

They walk on actin filaments
- In muscles
- In vesicular transport

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What are the three types of muscle cells?

1) Cardiac muscle (striated)
2) Skeletal muscle (striated)
3) smooth muscles

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What are skeletal muscles?

Muscles attached to the skeleton used for voluntary movement

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What does it mean for a skeletal muscle to be multinucleated?

Each myofiber results from the fusion of many cells.

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What are muscle fibers rich in mitochondria?

For energy supplements, they use glycolysis or aerobic respiration

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(skeletal muscles) What is a whole muscle?

It is “the organ” example the biceps

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(skeletal muscle) What is a muscle fiver?

It is a multinucleated muscle cell

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(Skeletal muscle?) What is a myofibril?

A contractile intracellular structure

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(skeletal muscle) What is a sacromere?

The contractile unit of a myofibril

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What are qualities of slow-twitch muscle fibers?

Has steady power
Endurant
Uses mostly fat
Aerobic metabolism (dense in capillaries, High myoglobin levels and red muscles/meat)

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What are qualities of fasr-twich muscle fibers?

Has explosive power
Fatigues easily
Glycolytic
Anerobic metabolism ( Less capillaries, Low myoglobin levels and White muscles/meat)

What are some cardiac muscle charachteristics?

striated
One central nucleus per cell
numerous mitochondria
interdigitate branches (no myofibrils)
rich in gap junctions between cells
Contracts independendly of nerve fibers (myogenic)

What is the excitation of cardiac muscles?

They are myogenic and involontary

What is the excitation of skeletal muscles

They are neurogenic and usually voluntary

What are som charachteristsics of smooth muscles?

Not striated
Filaments scattered throughout the cell
Connected and communicate via gap junctions (functions as a single unit)
Can contract in all dimensions

What are some important roles of smooth muscles?

Push food down alimentary tract
Control blood flow
Control respitory system
Enable child birth

What is the functions of a tendon?

- Attach muscles to the skeleton - Connective fibrous tissue

What are the functions of ligaments?

- Attach bone to bone (joints) - Fibrous tissue - Less eleastic than tendons

What is a non-mineralized skeleton (hydroskeleton)?

Fluids in the coelomic cavities is compressed by circular muscle.

What is an endoskeleton?

A combination of cartilage and bone, found in most vertebrates.

What is the neurocranium?

A skull bone that encloses the brain and paried sense organs (mitten av skallen)

What is the splanchnocranium?

A skull bone that with skeletal elements of branchial arches, encloses the pharynx (nedre delen av skallen, även gälar på fiskar)

What is the Dermatocranium?

Part of the skull that consists of mineralized dermal plates forming an armour. (toppen av skallen)

What is endochondral bone formation?

It means that the cartilage forms first, and bone replaces it. This is the case for neurocranium and splanchnocranium

What is intramembraneous bone formation?

When bone forms directly from dermal condensations. The case of dermatocranium.

What type of movement does the cortex control?

motor planning and visual feedback, adaptation to enviroment

What type of movement odes the basal ganglia control?

Controls the proper initiation of movement

What type of movement odes the brain stem + cerebellum control?

Can vary the speed and quality of movement (refinements)

What type of movement does the spinal cord control?

Motor neurons = the final common pathway for motor output

What does gradationof whole-muscle tension result from?

1) The number of muscle fibers contracting within a muscle 2) The tension developed by each contracting fiber

What does a motor unit consist of?

One motor neuron and all the muscle fibers that it stimulates

What happens when all muscle fibers are stimulated simultanously?

All muscle fibers conected to the unit contracts

What are myofibrils made of?

Many overlapping filaments of actin and myosin

What is a sacromere?

The smallest functional unit of striated muscle tissue.

How does myosin fibers "climb" along actin fibers?

With an alternating cycle of grasp-pull-release

What is the first step in the cross-bridge cycle?

1) the tension of myosin conformation with ATP hydrolysis

What is the second step in the cross-bridge cycle?

2) Binding of myosin to actin (=cross-bridge formation)

What is the third step in the cross-bridge cycle?

3) Structural change: myosin bends (=power stroke), ATP is released

What is the fourth step in the cross-bridge cycle?

4) Release of actin, requires binding of fresh ATP