Biological Interaction: Perception, Coordination, and Senses

1. Biological Interaction

The interaction function enables organisms to receive changes and stimuli from their environment.

1.1 Stages of Interaction

The interaction function is divided into three stages: perception of stimuli, processing of information, and generation of a response.

• Stimulus: A physical or chemical change that affects the body.
• Receptors: Specialized cells that receive stimuli and transmit information.

Types of Receptors:

• Internal: Perceive changes inside the body.
• External: Perceive changes outside the body.
• Mechanoreceptors: Perceive mechanical stimuli.
• Thermoreceptors: Perceive changes in temperature.
• Nociceptors: Perceive pain.
• Photoreceptors: Perceive changes in light.

1.2 Coordination Centers

Coordination centers receive information from receptors and generate appropriate orders.

• Nervous System: Analyzes internal and external stimuli, generating orders sent to effectors via nerve impulses. It coordinates fast, short-term responses.
• Endocrine System: Composed of endocrine glands that release hormones into the bloodstream. These hormones coordinate internal organs by triggering chemical reactions.

1.3 Effectors

Effectors are the organs responsible for executing the body’s response. They include:

• Muscles: Respond by contracting.
• Endocrine Glands: Respond by secreting substances.

2. Sensory Receptors

Humans possess five primary senses to perceive the external environment: smell, touch, taste, hearing, and sight.

2.1 Smell

Smell receptors are chemoreceptors sensitive to substances in the air.

2.2 Touch

There are three types of touch receptors: thermoreceptors, mechanoreceptors, and nociceptors.

2.3 Taste

Taste receptors are chemoreceptors sensitive to substances dissolved in saliva.

2.4 Hearing

Hearing receptors are mechanoreceptors. The human ear is divided into three parts: the outer ear, the middle ear, and the inner ear.

2.5 Sight

Sight receptors are photoreceptors sensitive to light. The human eye consists of:

• The Eyeball: A slightly flattened sphere filled with transparent fluids.
• Auxiliary Structures: Eyebrows, eyelids, eye muscles, and lacrimal glands, which protect the eyeball and enable movement.