Bios 114: Quiz 8

Brain Anatomy and Function

• Cerebrospinal Fluid (CSF)

  • Clear fluid surrounding the brain and spinal cord.

  • Functions to cushion and protect the brain, circulate nutrients and remove waste.

• Meninges

  • Three protective membranes covering the brain and spinal cord.

• Cerebrum

  • Largest part of the brain, responsible for higher brain functions such as thought, action, and emotion.

  • Divided into left and right hemispheres.

• Corpus Callosum

  • Thick band of nerve fibers connecting the left and right hemispheres of the cerebrum.

  • Facilitates communication between the two hemispheres.

• Gyri

  • The raised folds on the surface of the cerebrum.

• Sulci

  • The grooves between the gyri.

• Cerebellum

  • Located under the cerebrum, involved in coordination, balance, and motor control.

• Ventricles

  • Fluid-filled cavities within the brain that produce and contain cerebrospinal fluid.

• Diencephalon

  • Central part of the brain containing crucial structures for sensory information processing.

  • Major components: Thalamus and Hypothalamus.

• Thalamus

  • Relay station for sensory impulses (except smell) to the cerebrum.

• Hypothalamus

  • Regulates autonomic systems, hormones, and homeostasis (e.g., temperature, thirst, hunger).

• Pituitary Gland (Hypophysis)

  • Master hormone gland, controlling various physiological processes and other endocrine glands.

• Brain Stem

  • Connects the brain to the spinal cord, regulating vital functions such as breathing and heart rate.

  • Contains three parts: Midbrain, Pons, Medulla Oblongata.

• Midbrain

  • Involved in vision, hearing, and motor control.

• Pons

  • Connects the cerebellum to the brain and helps regulate breathing.

• Medulla Oblongata

  • Controls autonomic functions such as heart rate and blood pressure.

• White Matter

  • Composed of myelinated axons, facilitating speed of communication between brain regions.

• Grey Matter

  • Contains neuron cell bodies, dendrites, and unmyelinated axons, involved in processing and cognition.

Spinal Cord Structure

• Dorsal Nerve Cord (Spinal Cord)

  • Main pathway for transmitting information to and from the brain.

• Dorsal Root

  • Contains sensory neurons bringing information to the spinal cord.

• Dorsal Root Ganglion

  • Cluster of sensory neuron cell bodies located just outside the spinal cord.

• Ventral Root

  • Contains motor neurons that send signals from the spinal cord to muscles.

• Motor Neuron

  • Transmits impulses to muscle fibers to induce movement.

• Reflex Arc

  • The simplest neural pathway that controls a reflex action; involves sensory neurons, interneurons, and motor neurons.

Structure of a Neuron

• Cell Body

  • Contains the nucleus and organelles.

• Dendrites

  • Branch-like structures receiving signals from other neurons.

• Axons

  • Long projections transmitting signals away from the cell body.

• Schwann Cells

  • Cells that produce the myelin sheath around peripheral axons.

• Myelin Sheath

  • Insulating layer around axons, increasing transmission speed of electrical impulses.

• Nodes of Ranvier

  • Gaps in the myelin sheath allowing for faster signal transmission.

• Synapse

  • Junction between two neurons for signal transmission.

• Synaptic Knob

  • End of the axon where neurotransmitters are released.

• Synaptic Cleft

  • Space between the synaptic knob and adjacent neuron.

• Neuroglial Cells

  • Supportive cells providing protection and nourishment for neurons.

Nervous System Overview

• Central Nervous System (CNS)

  • Comprises the brain and spinal cord, responsible for processing information.

• Peripheral Nervous System (PNS)

  • Includes all cranial and spinal nerves, connecting the CNS to the body.

  • Subdivided into:

    • Cranial Nerves

    • Spinal Nerves

    • Sensory Receptors

Eye Anatomy

• Cornea

  • Transparent front part of the eye that refracts light to help focus images.

• Retina

  • Layer receiving light and converting it into neural signals.

• Choroid

  • Vascular layer providing blood supply to the eye.

• Rod Cells

  • Photoreceptors sensitive to low light conditions.

• Ciliary Body

  • Controls the shape of the lens for focusing.

• Cone Cells

  • Photoreceptors responsible for color vision and function well in bright light.

• Lens

  • Biconvex structure that focuses light onto the retina.

• Vitreous Humor

  • Jelly-like substance filling the eye, maintaining its shape.

• Iris

  • Colored part of the eye controlling the size of the pupil.

• Aqueous Humor

  • Fluid filling the eye's anterior chamber, providing nutrients and maintaining pressure.

• Pupil

  • Opening in the iris allowing light to enter the eye.

• Fovea Centralis

  • Small pit in the retina responsible for sharp vision.

• Optic Nerve

  • Transmits visual information from the retina to the brain.

• Sclera

  • Tough outer layer of the eye providing structure and protection.

• Optic Disc

  • Area where the optic nerve enters the eye; lacks photoreceptors (blind spot).

• Conjunctiva

  • Mucous membrane covering the front of the eye and inner eyelids.

Ear Anatomy

• Auricle/Pinna

  • External part of the ear that collects sound waves.

• Auditory Canal

  • Pathway leading sound waves to the eardrum.

• Tympanic Membrane

  • Ear drum that vibrates in response to sound waves.

• Eustachian/Auditory Tube

  • Connects the middle ear to the throat, equalizing pressure.

• Malleus, Incus, Stapes

  • Small bones in the middle ear that transmit vibrations to the inner ear.

• Cochlea

  • Fluid-filled structure where sound is converted into neural signals.

• Semicircular Canals

  • Structures involved in maintaining balance and spatial orientation.

Tongue Anatomy

• Taste Cells

  • Sensory cells that respond to chemical stimuli from food.

• Papillae

  • Small bumps on the tongue containing taste buds.

• Taste Zones

  • Regions of the tongue associated with different taste sensations (sweet, sour, salty, bitter, umami).