APPLIED RADIOLOGICAL ANATOMY

ANATOMY

MUSCULOSKELETAL AND SOFT TISSUE

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
How do muscles know when to contract?
A
When they receive messages from the nervous system
B
When it is cold outside
C
When receive messages from the blood
D
When your reflexes kick in
Explanation: 

Detailed explanation-1: -The motor neurons release a chemical, which is picked up by the muscle fibre. This tells the muscle fibre to contract, which makes the muscles move. Neurons carry messages from the brain via the spinal cord. These messages are carried to the muscles which tell the muscle fibre to contract, which makes the muscles move.

Detailed explanation-2: -A Muscle Contraction Is Triggered When an Action Potential Travels Along the Nerves to the Muscles. Muscle contraction begins when the nervous system generates a signal. The signal, an impulse called an action potential, travels through a type of nerve cell called a motor neuron.

Detailed explanation-3: -Motor neurons are covered with ion channels, which open in response to electrical signals from the brain. Once these ion channels are open, a series of cascading reactions allows the signal to reach the skeletal muscle cells, which ultimately results in muscle contraction.

Detailed explanation-4: -Cellular communication is mediated by lipids, fusogenic membrane proteins, and exosomes. Muscle-derived exosomes carry proteins and micro RNAs as cargo. Secreted factors such as IGF-1, TGF, and myostatin are also released by muscle cells providing local signaling cues to modulate muscle fusion and regeneration.

Detailed explanation-5: -Muscle contraction is the tightening, shortening, or lengthening of muscles when you do some activity. It can happen when you hold or pick up something, or when you stretch or exercise with weights. Muscle contraction is often followed by muscle relaxation, when contracted muscles return to their normal state.

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