Endocrine and nervous system

Journey to the Nervous and Endocrine system

One day I felt that I have pain in my leg so I decided to go to the doctor. He said he will check my legs for normal nerve function. He was holding a hammer. After that he said I will test your knee respond to the hammer, so the doctor knocked with a small hammer on the tendon below the knee.
A split second later, when the doctor tapped me with the hammer he said if your leg respond and have a reflex so it is good. I was curious how this reflex works, so to know the answer I decided to let the doctor explain it to me.


The doctor said in order to understand what happened you should understand the reflex arc to see how it works.
So first imagine that you are in a trip inside your body so as tapping the knee cap (patella) pulls on the tendon of the quadriceps femoris, which is an extensor muscle that extends the lower leg.

The Knee reflex arc

When the knee is tapped and this is the stimulus (something that causes a reaction in an organ or cell). Then we will move the receptors , the muscles in your leg have a stretch receptors which is (cells are specialized to react to a
specific stimulus). These are called receptors (they receive a stimulus) .

How the message is transmitted

So what can transmit information is the neuron for the electrical and chemical impulses. When the neuron is stimulated, it produces an electrical impulse that travels only within that neuron. Before the signal can move to the next cell, it changes into a chemical signal.
Neuron in rest must be ready to send a signal. So in order to do this it must have more negative charge inside than outside. So the difference between charges is resting potential. So energy needed to send a signal. So when neurons is stimulated, it produces a moving electrical impulse and it is action potential .
As the action potential moves along the axon, Na+ channels open. Na+ rushes into the cell, and the cell becomes positive. As the impulse moves forward, k+ Channels open. K+ flows out of the cell, and it becomes negative again, returning to its resting potential. Before the action potential can be passed to another neuron, it reaches the axon terminal, the end of the axon. After that it must go through a tiny gap between the neurons, called a synapse. After the action potential reach to the terminal, the terminal release chemicals in the synapse
these chemicals called neuorotransmitters .

Response to stimulus

so stretch receptor they react to a change in length of the muscle .
when the hammer hits the tendon at the , knee it makes a muscle in the front of your thigh longer (stretches)

That stimulates the stretch receptors stimulated , the nerve that receives this stimulus send an impulse to the spinal cord , so that sensory neuron carries the massage from the receptor to the central nervous system (the spinal cord and the brain )

Where it is relayed to a motor nerve .

the quadriceps muscle at the front to the thigh to contract and move the leg up .

so the motor neuron carries the massage from the central nervous system to the effector .

this is a reflex arc . so the sensory neuron connects to the motor neuron in the spinal cord . this is called a simple reflex arc . so it is involves only tow nerves and one synapse . the leg beings to jerk up while the brain is just becoming aware of the tap .

endocrine response to stress.

But that is all about the nervous system and for the endocrine system it is extremely connected to the nervous system and our body trip going to be completed.
patient: actually I am afraid about that my knee will not respond .
So that is a stimulus because the endocrine system is often compared with the nervous system, which also has the function of co-ordination and passing –instructions-, but by an independent mechanism.
Endocrine system producing a response to stimuli outside of your body, releases hormones that cause noticeably bodily changes as for example; heart rate increase.
Action potential will stimulate the hypothalamus receieves action potentials and releases hormones. The hormones will affect the pituitary gland wich will affect the adrenal.

So your adrenal gland notices chemical signals put out by the nervous system in response to any bodily stress.
Once signaled, the adrenal gland releases the hormones adrenaline into your bloodstream.
These hormones travel to a target cell, bind with the cell’s receptor site and cause complex chemical chain reactions that mobilize glucose and fatty acid.
Cellular energy reserves are increased and your muscles contract.
These unconscious and almost instantaneous chemical response bring about all the familiar feelings of stress.
All this happens in a matter of seconds as the body responds to an outside stimuli .

At the end

Your body will return to normal as soon as it has reached homeostasis, hence the stress response will stop. With this my dear we conclude our trip. So remember all the systems work in coordination to helps us in our survival.