Ramapo College of New Jersey 4

Eicosanoids

  • Eicosanoids are signaling molecules secreted by cells, crucial for immune responses and cellular communication.

  • Leukotrienes:

    • Secreted by helper T cells

    • Recruit B cells and killer T cells

    • Found in animals, differentiated from plant-derived eicosanoids

  • Prostaglandins:

    • Assist in healing and have various roles in bodily functions (e.g., inflammation, blood flow, and blood clotting).

Cell Communication

  • Cells secrete chemical signals that target other cells.

  • Target Cells:

    • Respond to specific signals

    • Can be identified by their tissue or organ designation

Signal Movement in Bodily Fluids

  • Chemical signals can be hydrophobic or hydrophilic:

    • Hydrophobic signals require proteins to transport through bodily fluids.

    • Hydrophilic signals can move freely in aqueous environments.

Types of Glands

  • Exocrine Glands:

    • Have ducts and secrete substances like saliva, tears, or digestive enzymes to a surface.

  • Endocrine Glands:

    • Ductless, release hormones directly into the bloodstream.

    • Examples include the pituitary gland and adrenal glands.

Hormonal Regulation

  • Hormones act like messengers traveling through blood to distant targets.

    • Growth Hormone:

      • Secreted by the pituitary gland, stimulates growth in various tissues, particularly bones.

    • Thyroid Hormones (T3 and T4):

      • Secreted by the thyroid gland, regulate metabolism and energy use.

      • Imbalances can affect weight and energy levels.

Feedback Mechanisms in Hormonal Regulation

  • Insulin:

    • Secreted by pancreas in response to high blood sugar.

    • Targets liver to convert glucose into glycogen, lowering blood sugar.

  • Glucagon:

    • Secreted by pancreas when blood sugar is low.

    • Stimulates breakdown of glycogen into glucose, raising blood sugar levels.

  • Both insulin and glucagon play crucial roles in maintaining blood sugar levels.

Diabetes Type Overview

  • Type 1 Diabetes:

    • Insulin production is insufficient. Treatment often involves insulin injections.

  • Type 2 Diabetes:

    • Body cells become resistant to insulin, requiring higher insulin levels for regulation.

    • Often linked to diet and lifestyle factors.

Adrenal Gland Function

  • Located above the kidneys; consists of the adrenal cortex and medulla.

  • Adrenal Cortex:

    • Produces steroid hormones (adrenocorticoids).

    • Mineralocorticoids: Target kidneys to reabsorb minerals.

    • Glucocorticoids: Enhance glucose metabolism during stress and raise blood sugar levels.

  • Adrenal Medulla:

    • Produces epinephrine and norepinephrine (formerly adrenaline), facilitating the fight-or-flight response.