Answer:
<h2>
potassium</h2>
Explanation:
The heartbeats of the heart are controlled by the sinoatrial node also known as the pacemaker of the heart. The impulse is generated in the conducting cells of the pacemaker as a result of the movement of sodium, potassium and calcium ions.
The sodium channels allow the movement of sodium into the cell which depolarizes the membrane from -60mv to -40 mv. At this point, the calcium gated channels open which allow the entry of the calcium in the cell which depolarizes the cell up to +5mv.
At this point, the potassium channels open which allows the potassium ions to move out of the cell. This repolarizes the cell and hence the cycle again begins. Reducing the permeability of the potassium ions help generate the autorhythmicity due to repolarization and thus is the correct answer.
The respiratory system contains the lungs, so the answer is C. Hope this helps.
Most people will have a minor neck problem at one time or another. Our body movements usually do not cause problems, but it's not surprising that symptoms develop from everyday wear and tear, overuse, or injury. Neck problems and injuries most commonly occur during sports or recreational activities, work-related tasks, or projects around the home.
Neck pain may feel like a "kink," stiffness, or severe pain. Pain may spread to the shoulders, upper back, or arms, or it may cause a headache. Neck movement may be limited, usually more to one side than the other. Neck pain refers to pain anywhere from the area at the base of the skull into the shoulders. The neck includes:
The bones and joints of the cervical spine (vertebrae of the neck).
The discs that separate the cervical vertebrae and absorb shock as you move.
The muscles and ligaments in the neck that hold the cervical spine together.
Neck pain may be caused by an injury to one or more of these areas, or it may have another cause. Home treatment will often help relieve neck pain caused by minor injuries.
Activities that may cause neck pain
Neck pain is often caused by a strain or spasm of the neck muscles or inflammation of the neck joints. Examples of common activities that may cause this type of minor injury include:
Holding your head in a forward posture or odd position while working, watching TV, or reading.
Sleeping on a pillow that is too high or too flat or that doesn't support your head, or sleeping on your stomach with your neck twisted or bent.
Spending long periods of time resting your forehead on your upright fist or arm ("thinker's pose").
Stress. Tension may make the muscles that run from the back of the head across the back of the shoulder (trapezius muscle) feel tight and painful.
Work or exercise that uses your upper body and arms.
Sudden (acute) injuries
Minor neck injuries may result from tripping, falling a short distance, or excessive twisting of the spine. Severe neck injuries may result from whiplash in a car accident, falls from significant heights, direct blows to the back or the top of the head, sports-related injuries, a penetrating injury such as a stab wound, or external pressure applied to the neck, such as strangulation.
Pain from an injury may be sudden and severe. Bruising and swelling may develop soon after the injury. Acute injuries include:
An injury to the ligaments or muscles in the neck, such as a sprain or strain. When neck pain is caused by muscle strain, you may have aches and stiffness that spread to your upper arm, shoulder, or upper back. Shooting pain that spreads down the arm into the hand and fingers can be a symptom of a pinched nerve (nerve root compression). Shooting pain is more serious if it occurs in both arms or both hands rather than just one arm or one hand.
A fracture or dislocation of the spine. This can cause a spinal cord injury that may lead to permanent paralysis. It is important to use correct first aid to immobilize and transport the injured person correctly to reduce the risk of permanent paralysis.
A torn or ruptured disc. If the tear is large enough, the jellylike material inside the disc may leak out (herniate) and press against a nerve or the spinal cord (central disc herniation). You may have a headache, feel dizzy or sick to your stomach, or have pain in your shoulder or down your arm.
he three steps in the process of DNA replication are initiation, elongation and termination.
Replication Basics. Replication depends on the pairing of bases between the two strands of DNA. ...
Initiation. ...
Elongation. ...
Termination.
Answer:
C. They break down food materials into forms the cell can use.
