Chapter 5 (A)

25問 • 1年前

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The following statement(s) is/are true about the muscular tissue:

It is one of the body’s four main tissues (together with the epithelial, connective and nervous tissues), Its structural unit is the muscle cell, also called muscle fibre

The muscle tissue will form:

Skeletal striated muscles, The organs responsible for body movements

The following types of muscles form the muscular system:

Striated (skeletal) muscles, under voluntary control, Smooth muscles which trigger spontaneous, involuntary contractions, The myocardium (heart muscle) which has involuntary, rhythmical contractions

Choose the correct associations referring to the three types of muscle tissue:

Central single nucleus – smooth muscle tissue, myocardium, Sarcomeres – skeletal striated muscle tissue – cardiac muscle tissue

Choose the statements which describe accurately the differences between the striated skeletal muscle and the cardiac muscle:

They have different locations, the striated skeletal muscle being inserted onto the bones, The striated skeletal muscle fibre is multinucleated, while the cardiac muscle fibre has a single nucleus, The striated skeletal muscle has a much faster contraction speed than the cardiac muscle

Choose the true statement(s) referring to the muscle tissue:

It is one of the four main tissues in the body, It has the ability to contract, It has the ability to perform mechanical work, The muscle cell (fibre) is the structural unit of the muscle tissue

The shape of muscle fibres in the various types of muscles can be:

Elongated, cylindrical with rounded ends in striated skeletal muscles, Fusiform with sharp ends in smooth muscles

The following statement(s) is/are true referring to the smooth muscle:

It can be unitary and multi-unit, The fibres of unitary smooth muscle have gap junctions, The smooth muscle fibre receives nerve impulses from the vegetative (autonomic) nerves

The following statement(s) is/are true about the cardiac muscle:

It receives impulses generated by the cells of the excito-conductor system, It is not under voluntary nervous control, It has a striated microscopic aspect

Choose the true statement(s) referring to the striated skeletal muscle:

Their tubular arrangement consists in two tubes/sarcomeres, located at the A – I junctions, It is controlled by the somatic nervous system

Which of the following statements characterize(s) the cardiac muscle?

It is present only in the structure of the heart (in the heart wall), Its fibres (often ramified) form a real network with adjacent fibres, Intercalated discs facilitate the propagation of contractions from one cell to the other

The following statement(s) is/are true about the smooth muscle:

It cytoplasm contains actin and myosin filaments, forming similar structures to that of microfibrils, The contraction of the rectum wall muscle contributes to the elimination of the rectal content, It has diffuse junctions where neurotransmitters are released

Which of the following statements is/are characteristic for the structure of the striated skeletal muscle fibre?

Each fibre contains 4-20 filiform filaments with a length up to 100μ, In sarcomeres, myofibrils are organised along their longitudinal axis, The repetitive distribution of sarcomeres gives them their characteristic striated aspect

The microscopic aspect of the sarcomere shows:

The presence of two types of myofilaments (actin and myosin), arranged parallel to each other, The presence of Z-line – the area in which the actin filaments of two adjacent sarcomeres are interconnected, The clear band divided into two equal halves by the Z-line is called I-band

The following statement(s) is/are true about the microscopic structure of the sarcomere:

Thin actin myofilaments and thick myosin myofilaments are arranged parallel to each other, The A-band is divided into two equal halves by the H zone which contains only myosin filaments, Thick filaments consist of myosin, a protein formed of two polypeptide chains twisted around each other

The actin filament:

Is thin and looks like a helix formed of two polypeptide chains twisted around each other, Contains tropomyosin molecules in the groove of the helix

The red muscle:

Contains a large quantity of myoglobin, an oxygen-storing protein, Is a slow or oxidative muscle, It can withstand muscle fatigue, due to the oxygen stored in the myoglobin, which will be used in cellular respiration

The white muscle:

Is a fast, glycolytic muscle (so called due to its high glycogen content), Rapidly uses ATP (adenosine triphosphate acid) but it cannot replace it as fast as it uses it, It has very little available oxygen necessary for cellular respiration

The following statement(s) is/are true about calcium ions (Ca 2+) in the muscle fibre:

Normally, in a resting cell, their concentration is very low in the sarcoplasm, They are constantly pumped out of or into the cell in the cell’s specialised smooth endoplasmic reticulum (sarcoplasmic reticulum), They are stored in the sarcoplasm reticulum reservoir and on the transverse tubule system (T tubules)

During the greatest muscle contraction in skeletal muscles:

The thin actin filaments are superposed, Sarcomeres reach their smallest size, The H-zone disappeared and the I-band greatly decreased in size

Filament sliding cycles in striated muscles:

Take place as long as adenosine triphosphate is available, Take place very quickly, at millions of myosin ends, Take place as long as there is a nerve stimulus

Myoglobin:

Is present in large quantities in red muscle fibres, Is the muscle pigment which stores oxygen necessary for cellular respiration

A neuromuscular junction consists of:

A single muscle fibre, very close to the nerve ending, but without touching it, The end of a single nerve cell which does not touch the sarcolemma of the muscle fibre, The synaptic cleft – a fluid filled space

Acetylcholine:

Is released in the synaptic cleft of the neuromuscular junction, Is a neurotransmitter which can also be released by certain neurons in the encephalon, Is bound to the receptors on the cellular membrane of the muscle fibre (sarcolemma)

Muscle contraction requires the following:

Acetylcholine - neurotransmitter, Sodium ions (Na+) which permeate the cell when acetylcholine is bound to the sarcolemma receptors

Chapter 1 (komplett)

X · 50問 · 1年前

Chapter 1 (komplett)

50問 • 1年前

Chapter 1 (A)