Human Interaction, Nervous and Endocrine Systems
1. The Interaction Process
This function includes a series of processes whose objectives are:
- To adapt the body to changing conditions, in the internal as well as external environment.
- To connect and coordinate the different parts of our body so that they work together.
1.1. Homeostasis
Homeostasis processes maintain the body’s stability when there are changes in the internal environment.
Homeostasis processes work like a feedback device. This means that when a variation is detected in a particular element, a series of mechanisms in the body start up to make the variation return to its normal state.
1.2. Systems that Participate in the Interaction Process
The organs and systems involved in the interaction process work the following way: the sensory organs receive information from the environment in the form of stimuli. The information is transformed into nerve impulses and transmitted to the nervous system. The nervous system receives the information, processes it, and gives a response, which is transferred to the effector organs.
2. The Neuron
They are made up of a cell body and two kinds of long extensions: dendrites and axons or neurites.
- Cell body: This contains the nucleus and other organelles, and is filled with cytoplasm.
- Axon: This is a long extension that is made up of cytoplasm and carries nerve impulses from the cell body to another neuron or cell.
- Dendrites: These are short, branched extensions of the cell body that receive nerve impulses from other neurons.
Neurons can be categorized:
- Depending on their structure, neurons can be unipolar, multipolar, or bipolar.
- Depending on their function, neurons are classified into three kinds: sensory neurons, motor neurons, and interneurons.
- Sensory neurons: These transmit information from the receptors to the most important nerve centers.
- Motor neurons: These transmit the signals from the nerve centers to the effector organs.
- Interneurons: These connect the sensory neurons and the motor neurons. They are located in the brain and spinal cord.
2.1. Electrical Signals
There are very small vesicles at the axon terminal that contain neurotransmitters. When the nerve impulse gets to the axon terminal, the vesicles break up and the neurotransmitters are released into the synaptic cleft.
3. The Nervous System
Functions:
- It receives the information transmitted by the sensory organs.
- It interprets that information and prepares adequate responses.
- It transfers the necessary signals to the effector organs.
- It coordinates all the organs so that they function correctly in our body.
- It carries out intellectual and mental functions.
- It is responsible for our emotions and feelings.
Nervous system anatomy:
3.1. The Central Nervous System
It is made up of nerve centers, which are responsible for integrating information received, coordinating it, and preparing a response. It is made up of the brain and the spinal cord, they are protected from possible injuries by:
- The skull and the spine.
- There are three membranes, called meninges. These are: the dura mater (the outermost layer), the arachnoid (the middle layer), and the pia mater (the innermost layer). Cerebrospinal fluid, found between each layer, cushions the effects of a blow to the nerve centers.
3.2. The Spinal Cord
Functions:
- It produces reflex actions.
- It carries sensory nerve impulses towards the brain.
4. The Endocrine System
The endocrine system is made up of endocrine glands; they release hormones directly into the bloodstream.
Hormones are organic molecules made up of an assorted chemical composition that reach the cells through the blood and they stimulate cells to perform various actions, such as coordinating, controlling, and regulating different organs.
Each hormone acts only on specific cells; these are called target cells.
Nervous system VS Endocrine system
The endocrine system depends on commands generated in the nervous system, mainly the hypothalamus, which is connected to the pituitary gland.
- Releases SH (stimulating hormones)
- SH pass to the pituitary gland
- SH takes over