Chapter 45
This presentation is the property of its rightful owner.
Sponsored Links
1 / 52

Chapter 45 PowerPoint PPT Presentation


  • 106 Views
  • Uploaded on
  • Presentation posted in: General

Chapter 45. Chemical Signals in Animals. Hormones. Hormones are chemical signals. The endocrine system consists of: Endocrine cells which are hormone-secreting cells and Endocrine glands which are hormone-secreting organs. Specific target cells respond to specific hormones.

Download Presentation

Chapter 45

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Chapter 45

Chapter 45

Chemical Signals in Animals


Chapter 45

Hormones

  • Hormones are chemical signals.

    • The endocrine system consists of:

      • Endocrine cells which are hormone-secreting cells and

      • Endocrine glands which are hormone-secreting organs.

  • Specific target cells respond to specific hormones.


Chapter 45

Primary Function of Hormones

  • Homeostasis

  • Growth and Development

  • Reproduction

  • Energy Metabolism

  • Behavior


Chapter 45

stimulates

glucose release from liver

glucagon from pancreas

stimulates

inhibits

blood glucose high

Negative Feedback Loop

blood glucose low


Chapter 45

Biological Cycles


Chapter 45

hormones

endocrine cell

receptor protein

target cell

Mechanism of Action on Target Cells

response


Chapter 45

hormones

endocrine cell

intracellular receptor

target cell

Mechanism of Action on Target Cells

response


Chapter 45

Tropic vs Nontropic Hormones

Tropic hormones- stimulate the production and secretion of hormones by other endocrine glands; ex. TSH

Nontropic hormones- stimulates cellular growth, metabolism, or other functions; ex. thyroxine


Invertebrate nervous systems clearly illustrate endocrine and nervous system interactions

Invertebrate nervous systems clearly illustrate endocrine and nervous system interactions

  • Invertebrates have a wide variety of hormones that are involved in the regulation of homeostasis.


Chapter 45

  • An example from hydra:

    • One hormone stimulate asexual reproduction.

    • Another hormone prevents sexual reproduction.

  • An example from a mollusk:

    • The hormone that regulates egg laying also inhibits feeding and locomotion.


  • Chapter 45

    • Arthropods have extensive endocrine systems regulating molting in insects and crustaceans.

      • The regulation of molting in insects.

        • Ecdysone also promotes the development of adult features.

        • Neurosecretory cells in the brain produce brain hormone (BH), which regulates the secretion of ecdysone.

      • Juvenile hormone (JH) promotes the retention of larval characteristics.


    Chapter 45

    • Different signal-transduction pathways in different cells can lead to different responses to the same signal.


    Chapter 45

    Major Endocrine Organs


    Chapter 45

    pineal gland

    hypothalamus

    pituitary gland

    Endocrine Organs of the Brain


    Chapter 45

    Pineal Gland

    Produces melatonin (synthesized from seratonin, a derivative of tryptophan)

    • Secreted directly in CSF to blood

    • High levels at night make us sleepy; low level during day

    • Pineal gland is stimulated by darkness and inhibited by light

    • Function in regulating circadian rhythms (sleep, body temp, appetite)  biological clock


    Chapter 45

    hypothalamus

    anterior pituitary

    posterior pituitary

    Pituitary Gland


    Chapter 45

    Posterior Pituitary

    Hypothalamus

    Posterior Pituitary

    Anterior Pituitary


    Chapter 45

    Hormones of the

    Posterior Pituitary

    Antidiuretic Hormone (ADH)

    Oxytocin (+ feedback)


    Chapter 45

    Anterior Pituitary

    Hypothalamus

    Posterior Pituitary

    Anterior Pituitary


    Chapter 45

    Hormones of the

    Anterior Pituitary

    • Growth Hormone (GH)

      • Dwarfism

      • Gigantism & Acromegaly

    • Thyroid Stimulating Hormone (TSH)

    • Adrenocorticotropic Hormone (ACTH)

    • Gonadotropins (FSH, ICSH, LH)

    • Prolactin (PRL)

    • Melanocyte-stimulating Hormone (MSH)


    Chapter 45

    Growth Hormone (GH)

    • Acts on the liver, stimulating it to release several polypeptide hormones.

    • Stimulates amino acid uptake and protein synthesis in target cells.

    • Ultimately stimulates cell growth (cell size and number), especially in muscle and bone.

    • Also stimulates fat breakdown.


    Gh levels

    strenuous exercise

    GH Levels

    sleep

    awake


    Thyroid stimulating hormone tsh

    Thyroid-Stimulating Hormone (TSH)

    • Acts on the thyroid gland, stimulating it to release T3 & T4

    • These thyroid hormones increase glucose catabolism and body heat production.

    • Negative feedback mechanism involved in regulating levels.


    Adrenocorticotropic hormone acth

    Adrenocorticotropic Hormone (ACTH)

    • Acts on the adrenal cortex, stimulating it to secrete glucocorticoids (e.g., cortisol).

    • Glucocorticoids promote the synthesis of glucose from noncarbohydrate sources such as amino acids, and fatty acids

    • Negative feedback mechanism involved in regulating levels.


    Chapter 45

    Thyroid Gland

    larynx

    thyroid

    trachea


    Chapter 45

    Thyroid Follicles


    Chapter 45

    Thyroid Hormones

    Thyroid gland selectively uptakes iodine to produce T3 & T4

    • Thyroxine (T4)

    • Triiodothyronine (T3)

    • Both control metabolic rate and cellular oxidation

    • Calcitonin (from parafolicular cells)- lowers blood CA ++ levels and causes CA++ reabsorption in bone


    Chapter 45

    Thyroid Hormone Regulation


    Chapter 45

    Thyroid Disorders

    • Hyperthyroidism (Grave’s, Goiter)

    • Hypothyroidism (Cretinism, Myxedima)


    Chapter 45

    parathyroid glands

    thyroid

    esophagus

    trachea

    Parathyroid Glands


    Chapter 45

    Parathyroid Hormone (PTH)

    • PTH release:

    • stimulates osteoclasts

    • enhances reabsorption of Ca++ by kidneys

    • increases absorption of Ca++ by intestinal mucosal cells

    • Hyperparathyroidism- too much Ca++ drawn out of bone; could be due to tumor

    • Hypoparathyroidism- most often follow parathyroid gland trauma or after removal of thyroid--- tetany, muscle twitches, convulsions; if untreatedrespiratory paralysis and death


    Chapter 45

    PTH Effects


    Chapter 45

    Pancreas


    Chapter 45

    Pancreas

    • Regulates glucose uptake by cells

    • Controlled via negative feedback: insulin & glucagon

    • Blood sugar level: 90 mg/mL


    Chapter 45

    Islets of Langerhan


    Chapter 45

    Insulin

    • Produced by the  cells of the Islets of Langerhan

    • Catalyze oxidation of glucose for ATP production

    • Lowers blood glucose levels by promoting transport of glucose into cells.

    • Stimulates glucose uptake by the liver and muscle cells.

    • Stimulates glycogen synthesis in the liver and muscle cells.

    • Also stimulates amino acid uptake and protein synthesis of muscle tissue


    Chapter 45

    Glucagon

    • Produced by the  cells of the Islets of Langerhans

    • Stimulates change of glycogen to glucose in the liver.

    • Synthesis of glucose from lactic acid and non carbohydrate molecules such as fatty acids and amino acids

    • Causes  in blood glucose concentration

    hypoglycemic- low blood sugar; deficient in glucagon


    Chapter 45

    Regulation of Blood Sugar Levels


    Chapter 45

    Diabetes Melitus


    Chapter 45

    Type I Diabeteshyposecretion of insulininsulin dependantjuvenile onsetType II Diabeteslate onset (adult)insensitivity of cells to insulinmanage by exercise & diet


    Adrenal glands

    adrenal cortex

    adrenal medulla

    Adrenal Glands


    Hormones of the adrenal medulla

    Hormones of the Adrenal Medulla

    • Adrenalin (epinephrine): converts glycogen to glucose in liver

    • Noradrenalin (norepinephrine): increases blood pressure

  • (sympathetic nervous system)

    • Corticosteroids: glucose levels)


  • Hormones of the adrenal cortex

    Hormones of the Adrenal Cortex

    • Glucocorticoids- cortisol

    • Decrease protein synthesis

    • Increase release and use of fatty acids

    • Stimulates the liver to produce glucose from non carb’s

    • Mineralcorticoids- aldosterone

    • Stimulates cells in kidney to reabsorb Na+ from filtrate

    • Increases water reabsorption in kidneys

    • Increases blood pressure

    • Sex Steroids- small amts (androgens)

    • Onset of puberty

    • Sex drive


    Cushing s syndrome

    Cushing’s Syndrome

    Hypersecretion of cortisone; may be caused by an ACTH releasing tumor in pituitary

    Symptoms: trunkal obesity and moon face, emotional instability

    Treatment: removal of adrenal gland and hormone replacement


    Addison s disease

    Addison’s Disease

    Hyposecretion of glucocorticoids and mineral corticoids;

    Symptoms- wt loss, low levels of plasma glucose and Na+ levels, high levels of K+

    Treatment- corticosteroid replacement therapy


    Chapter 45

    Thymus

    Located anterior to the heart

    Produces- thymopoetin and thymosin helps direct maturation and specialization of T-lymphocytes (immunity)


    Chapter 45

    Gonads

    Ovaries- produce estrogen and progesteroneresponsible for maturation of the reproductive organs and 2ndary sex characteristics in girls at puberty


    Chapter 45

    Female Reproductive System


    Chapter 45

    Gonads

    Testes- produce sperm and testosterone (initiates maturation of male repro organs and 2ndary sex characteristics in boys at puberty)


    Chapter 45

    Male Reproductive System


  • Login