Nervous & Endocrine Systems: Homeostasis

Lesson 5: Nervous System Working Together with Endocrine System to Maintain Homeostasis

• Learning objectives include describing how the nervous system coordinates and regulates feedback mechanisms to maintain homeostasis. This is designated as S10LT-IIIc-36.

Endocrine System

• Endocrine glands produce hormones and secrete them into the bloodstream.

Brain

• The brain is the central decision-making and communication center for the body.

Central Nervous System (CNS)

• The CNS is the first division which includes the brain and spinal cord.
• The brain has three main parts -forebrain, midbrain, and hindbrain.
• The brain is further divided into regions such as cerebrum, cerebellum, and brain stem.
• Different parts of the brain have distinct functions: for example the cerebrum is the center of intelligence and thought. The cerebellum plays a role in coordination, etc.

Spinal Cord

• The spinal cord connects the brain to the rest of the body.
• It's composed of gray and white matter.
• It transmits impulses to and from the brain.
• It's responsible for involuntary movements.

Peripheral Nervous System (PNS)

• The PNS involves all the nerves in the body.
  • Somatic Nervous System (SNS): regulates activities under conscious control, involving nerves controlling muscles and external sensory receptors like the eyes, ears, nose, skin and tongue.
  • Autonomic Nervous System (ANS): controls involuntary activities or those reflexive actions that proceed without conscious control in the body. Part of the ANS is divided into the sympathetic (fight or flight) and parasympathetic (rest and digest) nervous systems.

Pathway of the Nervous System

• Receptors are specialized structures within organs like eyes, ears, tongue, etc. These receptors detect stimuli from the environment and send signals.

  • Examples of receptors include photoreceptors (eyes), mechanoreceptors (ears), chemoreceptors (tongue), olfactory receptors (nose), nociceptors (pain), and thermoreceptors (temperature).

• Neurons are the basic structural and functional units in the nervous system.

  • A neuron is comprised of dendrites, a nucleus, cell body, axon, nodes of Ranvier, myelin sheath, and axon terminal.
  • Dendrites receive signals and transmit to the cell body, then to the axon.
  • Myelin sheath facilitates speedy signal transmission.

• Classification of neurons includes: sensory (affecting) neurons, motor (effective) neurons, and associative neurons (also in CNS).

What is Homeostasis?

• Homeostasis is the body's ability to maintain stable internal conditions despite environmental changes.
• It's regulated via feedback mechanisms managed by the endocrine and nervous systems

Feedback Mechanisms

• Negative feedback mechanisms are responses that oppose the initial change, reducing the variation from the normal range.
• Positive feedback mechanisms are responses that strengthen or continue the initial stimulus, enhancing the change, rather than correcting or reversing it.

Thermoregulation

• The body regulates its temperature through mechanisms such as shivering (heating) and sweating (cooling).

Childbirth

• Childbirth is an example of positive feedback.
• Stretching of the uterine walls activate receptors, which triggers a release of oxytocin that enhances contractions and eventually leads to delivery.

Hormones in the Blood

• The brain monitors the hormones and signals the endocrine system based on its detected changes.
• The endocrine system plays a crucial role in maintaining homeostasis.

Processing Questions

• The processing questions pertain to the impact of environmental factors on homeostasis in the body and how hormones contribute to maintaining homeostasis, as well as what homeostasis is, and why it's important.

Explore how the nervous and endocrine systems maintain homeostasis. Discover how the brain, spinal cord, and endocrine glands coordinate body functions via feedback mechanisms. S10LT-IIIc-36 covers components and their roles.