ewe

BIOL 245 Lab Midterm – Practice Quiz Study Notes

Part 1: Neurons (Exercise 15)

• Neuron Functions

  • Neurons are specialized cells responsible for receiving and transmitting signals in the nervous system.

  • Key Parts of a Neuron:

  • Axon: Transmits signals away from the neuron.

  • Dendrite: Receives incoming signals.

  • Axon terminal: Releases neurotransmitters into the synapse.

  • Myelin sheath: Insulating layer that speeds up nerve conduction.

• Neural Signal Pathways

  • Neurons can transmit information to the central nervous system (CNS) or the peripheral nervous system (PNS):

  • Motor neuron: Carries signals away from the CNS to muscles.

  • Sensory neuron: Carries signals toward the CNS from sensory receptors.

  • Interneuron: Connects neurons within the CNS.

• Connective Tissue Layers

  • Epineurium: Surrounds the entire nerve.

  • Perineurium: Surrounds a fascicle (bundle of axons).

  • Endoneurium: Surrounds individual axons.

• Neuron Cell Bodies

  • In the PNS, a collection of neuron cell bodies is called a ganglion.

  • In the CNS, it is referred to as a nucleus.

Part 2: Brain (Exercise 17)

• Brain Functionality

  • Cerebellum: Controls balance and coordination.

  • Brainstem Parts:

  • Composed of three parts: Pons, medulla, midbrain.

  • Brain Surface Features:

  • Gyrus: Raised ridge on the brain surface.

  • Sulcus: Groove on the brain surface.

• Central Nervous System

  • The CNS consists of the brain and spinal cord.

  • Meninges Layers:

  • Dura mater: Outermost layer.

  • Arachnoid mater: Middle layer.

  • Pia mater: Innermost layer closest to the brain.

Part 3: Reflexes (Exercise 21)

• Reflex Explanation

  • A reflex is defined as an automatic response to a stimulus, not requiring conscious thought.

• Types of Reflexes

  • Knee-jerk reflex: Also known as the patellar reflex.

  • The structure that detects a stimulus in the reflex arc is called a receptor (e.g., muscle spindle).

Part 4: Sensation (Exercise 22)

• Receptor Types

  • Exteroceptors: Detect external stimuli (e.g., light, sound).

  • Proprioceptors: Detect body position and movement.

  • Interoceptors: Respond to internal body stimuli (not primarily covered in quiz).

  • Nociceptors: Respond to pain stimuli (not primarily covered in quiz).

• Key Sensory Processes

  • Transduction: The process of converting a stimulus into a nerve signal.

Part 5: Vision (Exercise 23–24)

• Eye Structure

  • Iris: The colored part of the eye responsible for regulating light entry through the pupil.

  • Lens: The structure responsible for focusing light onto the retina.

  • Photoreceptors:

  • Cones: Responsible for color vision.

  • Rods: Responsible for vision in low light (not primarily covered in quiz).

  • Optic disc: The blind spot of the eye where there are no photoreceptors.

Part 6: Hearing & Equilibrium (Exercise 25)

• Middle Ear Structures

  • The small bones of the middle ear are collectively known as the ossicles.

  • Three Ossicles:

    • Malleus (hammer), Incus (anvil), Stapes (stirrup).

• Hearing Mechanism

  • The cochlea is responsible for hearing, utilizing the fluid movement to stimulate nerve signals.

  • The semicircular canals detect rotational acceleration important for balance.

  • Maculae detect linear acceleration (orientation of the head with respect to gravity).

Answer Key

1. B

2. B

3. C

4. C

5. B

6. B

7. A

8. B

9. B

10. C

11. C

12. C

13. B

14. B

15. C

16. C

17. B

18. B

19. B

20. C

21. B