Endocrine System - PowerPoint PPT Presentation

1 / 44
About This Presentation
Title:

Endocrine System

Description:

Endocrine System Biology 211: Anatomy & Physiology 1 Tony Serino, Ph.D. Biology Department Misericordia University – PowerPoint PPT presentation

Number of Views:64
Avg rating:3.0/5.0
Slides: 45
Provided by: Preferred99
Category:

less

Transcript and Presenter's Notes

Title: Endocrine System


1
Endocrine System
  • Biology 211 Anatomy Physiology 1
  • Tony Serino, Ph.D.
  • Biology Department
  • Misericordia University

2
Endocrine System
  • Controls and modifies the internal environment by
    releasing chemicals (hormones) into the blood
  • Slower response time but longer duration of
    action compared to nervous system

3
Chemical Messengers (hormones)
  • Hormone secreted by cell into blood and acts on
    another cell some distance away
  • Neurohormone secreted by neuron into blood to
    affect a target cell some distance away
  • Local hormones secreted by cell into
    interstitial fluid to affects cells nearby
  • Paracrines affect neighboring cells
  • Autocrines affect the secreting cell
  • Pheromones secreted by cell onto body surface to
    affect cells of another individual

4
Hormones
  • Chemical Classification
  • Amines single or few amino acids, most water
    soluble
  • Epinephrine, Thyroxine (but water insoluble),
    Melatonin
  • Proteins short to long chains of amino acids
    water soluble
  • GH, FSH, LH, Insulin, Glucagon, ADH, etc.
  • Steroids derivatives of cholesterol water
    insoluble
  • Estrogen, Testosterone, Progesterone, Cortisol,
    Aldosterone

5
Steroid Hormones
6
Characteristics Common to all Hormones
  • Must have target cell with appropriate receptor
    molecules
  • Receptor-hormone complex must trigger events in
    target cell that changes its physiology
  • Mechanisms for deactivating the hormone response
    must be present

7
Controlling Hormone Response
  • Half-life of the hormone
  • Physiological range
  • Modifying target cell response
  • Up and down regulation
  • Turning off secretion
  • Negative feedback
  • Control by other hormones, neurons and metabolites

8
Control of Hormone Secretion
9
Mechanisms of Hormone Action
2nd messengers
Water Soluble
Water Insoluble
Carrier protein
10
2nd Messengers cAMP
11
2nd Messengers IP3 and Ca-Calmodulin
12
Steroid Hormone Transduction
13
Different Styles of Secretion
  • Prohormone a hormone that is made as a larger
    (inactive form) that must be changed prior to
    secretion (allows for storage of hormone in
    secreting cell)Ex. proinsulin,
    pro-opiomelanocortin
  • Prehormone a hormone that is secreted in an
    inactive form that must be changed near or in the
    target cellEx. Thyroxine, Angiotensinogen

14
Proinsulin
15
Types of Endocrine Disorders
  • Hypersecretion
  • Too much secretion of the hormone
  • Hyposecretion
  • Too little secretion of hormone
  • Hyporesponsiveness
  • Normal secretion, but little to no response by
    target cells

16
Endocrine Glands
17
Hypothalamus Control of Pituitary
18
Posterior Pituitary
19
Anterior Pituitary
20
Control of Growth
  • Growth periods prenatal and postnatal (consists
    of pre-puberal (especially the first 2 years
    infancy) and puberty
  • Several factors influence growth genetics, diet,
    health, and hormonal balance
  • Prenatal growth dominated by insulin secretion,
    post-natal dominated by GH, thyroxine, and sex
    hormones

21
GH secretion and effects
GH secretion stimulated by exercise, fasting,
sleep (diurnal rhythm), stress, decreased plasma
glucose, increased plasma AA (such as after a
high protein meal)
Increase differentiation
Increase protein synthesis
(increase mitosis)
22
GH interactions with other Hormones
  • Thyroxine essential and permissive for GH
  • Needed to maintain energy levels for growth
  • Increases sensitivity of target cells to GH
    effects
  • Insulin essential for GH effects
  • Dominant hormone for pre-natal growth
  • Estrogen and Testosterone surge at puberty
    stimulates GH release, synergistic with GH
    anabolism also trigger epiphyseal closure
  • Cortisol anti-growth effects decrease GH
    secretion, cell division, and increase catabolism

23
GH pathologies
  • Hypersecretion
  • Gigantism in children with responsive epiphyseal
    plates
  • Acromegaly in adults, with closed epiphyseal
    plates

24
GH pathologies
  • Hypofunction
  • Dwarfism in children
  • Pituitary decreased GH secretion
  • Laron decreased responsiveness due to lack of GH
    receptors

28 yo woman withpituitary dwarfism 45 tall
Achondroplastic Dwarfism (genetic dwarf) due to
failure of cartilage to form in epiphyseal plate
25
Thyroid Location
26
Thyroid Follicle
(follicular cells ? thyroxine)
Parafollicular cells ? calcitonin
27
T3 T4 Formation and Secretion
28
T3 T4
29
Control of Thyroxine Secretion
Short loop
Long loop
30
Thyroid Malfunction
  • Hypothyroidism
  • Endemic goiters due to iodine deffeicency
  • Cretinism i thyroxine in child results in
    igrowth (dwarf) and severe mental retardation
  • Myxedema i thyroxine in adult, leads to swelling
    of tissues plus other symptoms

31
Cretinism
32
Thyroid Malfunction
  • Hyperthyroidism
  • Toxic goiters (Graves disease) Ab may stimulate
    thyroid without negative feedback control
  • Exophthalmos symptom present in many
    hyperthyroid patients

33
Parathyroid Location
34
Parathyroid
35
PTH Actions
  • Stimulates resorption of bone ? hCa and PO4- in
    blood
  • Stimulates Ca absorption in intestine (active
    Vit. D3 necessary for Ca absorption)
  • Stimulates Ca reabsorption and PO4- excretion in
    kidney
  • Stimulates Vit. D3 formation (skin) and
    activation (kidney)
  • Vital for life

36
Adrenal Location and Structure
37
Adrenal Layers
(Epinephrine (adrenalin))
(Androgens)
(Glucocorticoids (cortisol))
(Mineralocorticoids,(Aldosterone))
38
GAS (General Adaptation Syndrome)
39
Adrenal Malfunction
  • Hypersecretion
  • Cushings syndrome increase in glucocorticoids
  • Usually due to over secretion of ACTH by
    pituitary or from adrenal cortex tumors
    stimulating an increase in glucocorticoids.
    Characteristic obesity of trunk only and
    development of buffalo hump (a fat pad behind
    the shoulders). Will develop hypertension,
    atherosclerosis, muscular weakness and fatigue.
  • Conns syndrome excess amount of aldosterone
  • Salt imbalance, water retention, hBP, muscle
    weakness
  • Adrenogenital syndrome too much androgen
  • Premature sexual development in children or
    masculinization in women

40
Cushings
Obesity of trunk
(buffalo hump)
41
Adrenogenital syndrome
A 15 yo girl, note typical masculinebuild, under
developed breasts, andexcessive body hair
42
Adrenal Cortex Malfunction
  • Hyposecretion Addisons disease
  • Due to decrease amounts of mineral and
    glucocorticoids
  • Can be due to over use of steroids or an
    autoimmune mechanism resulting in destruction of
    the gland
  • Dehydration, K loss, iBP, fatigue, pigmentation
    deepening (bronzing of skin) may be symptom of
    loss of negative feedback

43
Pineal Gland
  • Plays a major role in circadian rhythm control
    through its sympathetic connection to the
    hypothalamus
  • Melatonin increases at night and decreases during
    daylight
  • Implicated in the control of major life changes
    (such as the onset of puberty and adulthood

44
Thymus Gland
  • Bilobed organ that is largest in children, but
    begins to regress sharply at the onset of puberty
    (around age 11)
  • It is the site of T-cell lymphocyte production
    and produces hormones (such as, thymosin) that
    modifies their physiology
Write a Comment
User Comments (0)
About PowerShow.com