BIOL 1062: Test Two Outline (Nervous & Endocrine Systems)

Vocabulary flashcards covering test logistics, nervous system divisions and neuroanatomy, endocrine signaling, pituitary function, stress response, and hormonal homeostasis for BIOL 1062 Test Two.

What are the two anatomical divisions of the nervous system?

1. Central Nervous System (CNS)

2. Peripheral Nervous System (PNS)

Briefly describe the Central Nervous System (CNS)

• What does it consist of?

• What does it do?

• Main framework of the body

  • Includes:

    • Brain

    • Spinal Cord

• Processess, interprets and stores information

  • Issues orders to muscles, glands, organs

Briefly describe the Peripheral Nervous System (PNS)

• What does it consist of?

• What does it do?

• Connection of nerves into/out of the CNS

  • Transmits information to/from the CNS

Label and describe each part of the neuron

A. Dendrites:

• Extensions that pick up signals from surroundings and send the impulses to the Cell Body

B. Cell Body

• Contains nucleus and other organelles

• Processes incoming signals

C. Axon

• Conducts nerve impulses away from the Cell Body

D. Myelin

• Lipid-based covering around axon

E. Nodes of Ranvier

• Only in myelinated neurons

  • Regions of the axon without myelin; gaps between myelin

F. Axon Terminal

• Ends of the neuron

• Used in communication with other neurons or effectors (muscles, glands)

What is the role of Neuroglial Cells in the CNS?

• Microglial

  • Immune cells in the brain

    • Respond to pathogens/bacteria/damage in the environment

• Oligodendrocytes:

  • Produces/forms myelin sheaths for neurons in the CNS

• Ependymal:

  • Secretes Cerebrospinal Fluid (CSF)

    • CSF homeostasis

  • Cleaning of waste in brain

• Astrocytes:

  • Provide nutrients to neurons for growth and protection

  • Essential for formation/maintenance of the Blood Brain Barrier (BBB)

    • BBB filters incoming material

What is the role of Neuroglial Cells in the PNS?

• Schwann Cells:

  • Wrap around an axon and form a myelin sheath

• Satellite Cells:

  • Surround the cell body of some neurons in the PNS

    • Provides nutrient support and protection

What are the three classes of neurons and their function?

1. Sensory (Afferent) Neurons: “A” for approach/bring into system

   • Takes messages from the environment to the CNS

     • Myelinated

       • May have specialized endings/receptors that detect changes in the environment

1. Interneuron

   • Receives input from sensory neurons and other interneurons

     • Not myelinated

       • Summarizes messages and communicates with motor neurons

2. Motor (Efferent) Neurons: “E” for exit/taking out of system

   • Carries messages from the CNS to an effector (output; muscle/gland)

What kind of conduction occurs in Unmyelinated vs Myelinated Neurons?

• Unmyelinated Neuron:

  • Continuous conduction:

    • Action potential moves slowly through the axon

• Myelinated Neuron:

  • Saltatory Conduction:

    • Myelin sheath speeds up the movement of electrical impulses

      • Action potential jumps from one Node of Ranvier to another

        • Node of Ranvier: gap between myelinated segments

What is the Action Potential?

• Series of quick changes in voltage across a cell membrane

  • Electrical signal quickly travels down a cell membrane, transmitting information

Electrochemical Synapse

A junction that facilitates signal transmission between pre-synaptic and post-synaptic neurons using synaptic vesicles.

Cerebrum

One of the four major parts of the brain, characterized by lobes and structures that connect and separate the left and right hemispheres.

Diencephalon

One of the four major divisions of the brain that encompasses specific subdivisions, including the hypothalamus.

Limbic System

A functional brain network that includes components such as the Amygdala and Hippocampus.

Somatic Reflex Arc

A neural circuit in which three distinct classes of neurons interact to generate a somatic reflex response.

Autonomic Nervous System

The nervous system division consisting of sympathetic and parasympathetic branches that exert opposing regulatory effects on target organs (e.g., increasing versus decreasing heart rate).

Tropic Hormone

A category of hormone distinguished from somatic hormones by the way it is directed toward and stimulates another endocrine target cell.

Posterior Pituitary

The pituitary lobe connected to the hypothalamus that stores and releases two hormones synthesized by hypothalamic cells via positive or negative feedback mechanisms.

Anterior Pituitary

The glandular lobe connected to the hypothalamus that secretes regulatory hormones such as Thyroid-Stimulating Hormone (TSH) and Adrenocorticotropic Hormone (ACTH) to maintain systemic homeostasis.

Antagonistic Hormones

Pairs of opposing hormones produced by endocrine glands that act in balance to regulate physiological homeostasis, such as the regulation of calcium and glucose levels.