Understanding Interaction, Homeostasis, and the Nervous System

Interaction and Homeostasis

Interaction includes a series of processes whose object is to adapt the body to changing conditions in the internal and external environment. It connects and coordinates the different parts of our body so that they work together.

Homeostasis is the process that maintains the body's stability when there are changes in the internal environment. This process works as a feedback device, meaning 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.

Systems Participating in the Interaction Process

• Sensory Organs: Capture the stimulus, which is transformed into a nerve impulse and transmitted to the nervous system.
• Nervous System: Analyzes, integrates, and processes the information and elaborates a response.
• Effector Organs: Execute the response. These are the skeletal and muscular systems, and the endocrine system.

Skeletal and Muscular Systems

Motor response.

Endocrine System

Secretory response.

The Neuron

The anatomical and physiological unit of the nervous system, specialized in the transmission of nerve impulses. Its ability to reproduce is limited.

Shape and Structure

• Cell Body: Contains the nucleus and most of the organelles.
• Axon: A cytoplasmic extension that transmits nerve impulses.
• Dendrites: Short extensions that receive nerve impulses.

Cells According to Their Structure

They can be unipolar, multipolar, and bipolar.

Cells According to Their Function

• Sensory Neurons: Transmit information from receptors to nerve centers.
• Motor Neurons: Transmit the responses from the nerve centers to the effectors.
• Interneurons: Connect the other types of neurons. They are located in the brain and in the spinal cord.

Synapses

They are functional connections that allow the transmission of nerve impulses. They are found between the end of the axon of one neuron and a dendrite of an adjacent neuron.

Types of Pathways

• Divergent: Transmit the nerve impulse from one to different neurons.
• Convergent: From different neurons to one neuron.

The Nervous System

Receives information from the sensory organs, interprets the information and makes a response, transforms the orders to the effector organs, coordinates the functioning of the body, performs intellectual and mental functions, and is responsible for emotions and feelings.

It is made up of the Central Nervous System (CNS) and the Peripheral Nervous System (PNS).

The Central Nervous System

It receives and processes sensory information, initiates responses, stores memories, and generates thoughts and emotions. It is made up of the brain and the spinal cord, which are protected by the skull and the spine.

The Brain

Receives and processes sensory information and initiates responses. It stores memory and generates thoughts and emotions.

The Spinal Cord

Conducts signals from and to the brain and controls reflex activities.

There are 3 membranes with cerebrospinal fluid called meninges between the protecting bones and the organs. They are the dura mater, the arachnoid, and the pia mater.

Central Nervous System Tissues

• Grey Matter: Neuronal bodies and dendrites; they are control centers that perform certain functions.
• White Matter: Neuronal axons covered in myelin.