Questions: Question 41 (2 points) Which muscle(s) can contract without the need for nervous stimulation? cardiac muscle smooth muscle skeletal muscle smooth and cardiac muscle Question 42 (2 points) Arrange the following list of biochemical events in the correct sequence. (1) An action potential is conducted deep into the muscle fiber by the T tubule. (2) Calcium ions bind to troponin. (3) The membranes of the sarcoplasmic reticulum become more permeable to calcium ions. (4) Calcium ions diffuse into the sarcoplasm around the myofibril. (5) The troponin-tropomyosin complex moves exposing active sites. 1,4,3,2,5 1,3,2,5,4 1,2,3,4,5 1,5,2,3,4 1,3,4,2,5

Question 41 (2 points)

Which muscle(s) can contract without the need for nervous stimulation?
cardiac muscle
smooth muscle
skeletal muscle
smooth and cardiac muscle

Question 42 (2 points)

Arrange the following list of biochemical events in the correct sequence.
(1) An action potential is conducted deep into the muscle fiber by the T tubule.
(2) Calcium ions bind to troponin.
(3) The membranes of the sarcoplasmic reticulum become more permeable to calcium ions.
(4) Calcium ions diffuse into the sarcoplasm around the myofibril.
(5) The troponin-tropomyosin complex moves exposing active sites.
1,4,3,2,5
1,3,2,5,4
1,2,3,4,5
1,5,2,3,4
1,3,4,2,5

Transcript text: Question 41 (2 points) Listen Which muscle(s) can contract without the need for nervous stimulation? cardiac muscle smooth muscle skeletal muscle smooth and cardiac muscle Question 42 (2 points) Listen Arrange the following list of biochemical events in the correct sequence. (1) An action potential is conducted deep into the muscle fiber by the $T$ tubule. (2) Calcium ions bind to troponin. (3) The membranes of the sarcoplasmic reticulum become more permeable to calcium ions. (4) Calcium ions diffuse into the sarcoplasm around the myofibril. (5) The troponin-tropomyosin complex moves exposing active sites. $1,4,3,2,5$ $1,3,2,5,4$ $1,2,3,4,5$ $1,5,2,3,4$ $1,3,4,2,5$

Solution

Question 41:
The answer is the last one: smooth and cardiac muscle.
Explanation:

Cardiac muscle: Correct. Cardiac muscle can contract without nervous stimulation due to the presence of pacemaker cells that generate rhythmic impulses.
Smooth muscle: Correct. Smooth muscle can also contract without direct nervous stimulation, often responding to hormonal or local chemical signals.
Skeletal muscle: Incorrect. Skeletal muscle requires nervous stimulation to contract.
Smooth and cardiac muscle: Correct. Both types of muscle can contract without the need for nervous stimulation, as explained above.

Question 42:
The correct sequence is: $1,3,4,2,5$.
Explanation:

(1) An action potential is conducted deep into the muscle fiber by the $T$ tubule. This is the initial step that triggers the subsequent events.
(3) The membranes of the sarcoplasmic reticulum become more permeable to calcium ions. The action potential causes this change in permeability.
(4) Calcium ions diffuse into the sarcoplasm around the myofibril. Once the sarcoplasmic reticulum is more permeable, calcium ions move into the sarcoplasm.
(2) Calcium ions bind to troponin. The presence of calcium in the sarcoplasm allows it to bind to troponin.
(5) The troponin-tropomyosin complex moves exposing active sites. The binding of calcium to troponin causes this complex to move, allowing muscle contraction to occur.

In summary, the correct answers are: