Ch. 13 Endocrine System Pt.2 Pt. 2

Auditory System Anatomy

  • Ears Anatomy:

    • Cochlea:

    • Description: Looks like a cinnamon bun or snail.

    • Internal Structure: When sliced open, reveals circular areas.

    • Function: Houses the organ of hearing (organ of Corti) within the cochlear duct (scala media).

    • Fluid in Cochlea:

    • Types: Different types of fluids present in the cochlea, specifically in various ducts/scala.

Eye Anatomy

  • Components of the Eye:

    • Sclera:

    • Definition: The white part of the eye.

    • Iris:

    • Definition: The colored part of the eye.

    • Photoreceptors:

    • Types:

      • Cones: Detect color.

      • Rods: Detect light.

Auditory Functions

  • Three Bones in the Ear:

    • Malleus (Hammer)

    • Incus (Anvil)

    • Stapes (Stirrup)

    • Function: These bones amplify sound vibrations and conduct them to the inner ear.

  • Tympanic Reflex:

    • Definition: An involuntary response that protects the ear from sound-induced damage by stiffening the tympanic membrane. Similar to a stiff arm in sports.

Endocrine System Overview

  • General Functions:

    • Secretion of hormones

    • Maintaining homeostasis

    • Communication and control in the body

Thyroid Gland

  • Hormones:

    • Thyroxine (T4)

    • Triiodothyronine (T3)

    • Calcitonin:

    • Produced by the thyroid gland.

    • Function:

      • Controls blood calcium and phosphate levels through osteoblast and osteoclast activity.

      • Osteoblast: Builds bone.

      • Osteoclast: Breaks down bone.

    • Effect on kidneys: Increases excretion of calcium and phosphate.

Parathyroid Glands

  • Location: Located on the back side of the thyroid gland.

    • Typical count: Four parathyroid glands.

  • Hormone Secreted:

    • Parathyroid Hormone (PTH):

    • Function: Increases blood calcium levels and reduces blood phosphate levels.

    • Mechanism: Acts on bones, kidneys, and intestines to regulate calcium homeostasis.

Adrenal Glands

  • Location: Sits atop the kidneys.

    • Structure: Pyramid-shaped with two main parts:

    • Adrenal Cortex:

      • Hormones Produced:

      • Aldosterone: Regulates water retention and sodium conservation.

      • Cortisol: The stress hormone, affecting glucose metabolism, inhib