Homeostasis, Hormones - PowerPoint PPT Presentation

Loading...

PPT – Homeostasis, Hormones PowerPoint presentation | free to download - id: 7a65a2-NWQ2M



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Homeostasis, Hormones

Description:

6.5: (Nerves, Hormones, &) Homeostasis 6.5.8 - Pg 110-Type II Diabetes Occurs later in life, as an adult Insufficient amounts of insulin are produced or the body has ... – PowerPoint PPT presentation

Number of Views:22
Avg rating:3.0/5.0
Slides: 67
Provided by: Monic172
Learn more at: http://ibbiologydesouza.weebly.com
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Homeostasis, Hormones


1
Homeostasis, Hormones Excretion
  • 6.6, D.5

2
Homeostasis
  • The human body works best under the following
    conditions
  • Body temperature of 37C
  • 0.1 blood sugar level
  • Blood pH level of 7.4
  • The external environment can alter these levels
  • Ex Outside temperature, physical activity,
    meals

3
HOMEOSTASIS
  • HOMEOSTASIS is the maintenance of the internal
    environment within an acceptable range, despite
    fluctuations in the external environment.
  • It creates a dynamic equilibrium a stable
    condition with fluctuating limits

4
Homeostasis
  • Requires constant monitoring and feedback about
    body conditions.
  • Homeostasis requires the interaction of several
    regulatory systems
  • I.e. Nervous system, respiratory system,
    endocrine system, the excretory system, the
    circulatory system.

5
(No Transcript)
6
Ex of Biological Homeostasis
  • Blood pH
  • Carbon dioxide concentration
  • Blood glucose concentration
  • Body temperature
  • Water balance
  • Blood pressure

7
Whats wrong with this graph?
8
Blood pH
  • Homeostatic level is pH 7.4
  • Narrow acceptable range 7.35-7.45
  • lt 7.35 acidosis
  • gt7.45 alkalosis
  • Non-homeostatic levels can cause blood proteins
    and enzymes to ionize and change shape and
    function.

9
Blood pH
  • Blood pH is maintained by the carbonic
    acid-bicarbonate buffer system
  • BUFFER substance that maintains pH
  • H2O CO2 H2CO3 HCO3 -
    H
  • water carbon carbonic
    bicarbonate hydrogen
  • dioxide acid
    ion ion

10
Low pH
  • Ex after eating a vinaigrette salad, H ions
    will enter the bloodstream, and the blood will
    become too acidic (pH to low!)
  • The increase in H means that there is a greater
    chance of HCO3- ions finding a H and forming
    H2CO3, thus increasing the pH

11
High pH
  • When a base enters the blood stream, the pH will
    rise making it more basic because the base will
    bond with H and remove them from the blood.
  • To compensate, H2CO3 ionizes to replace the
    missing H and lower the pH back to acceptable
    ranges

12
Carbon Dioxide Concentration
  • Oxygen and Carbon Dioxide concentration are
    maintained with the aide of chemoreceptors in the
    walls of certain blood vessels that can cause an
    increase or decrease in breathing rate.

13
Negative Feedback Systems
  • Mechanisms that make adjustments to bring the
    body back within an acceptable range (like a
    thermostat)
  • With negative feedback, the result of a process
    causes a reversal of the result.
  • Homeostasis relies on negative feedback systems
    to maintain homeostatic levels

14
Negative Feedback
  • A thermostat is an example of negative feedback.

Temperature Rises
Heater switched off
Temp change Detected by Thermostat
Temp Decreases
Heater switched on
Temp Decreases
Temp change Detected by Thermostat
Temperature Rises
15
  • All homeostatic control system have 3 functional
    components
  • A monitor/sensor
  • Measure the current situation
  • A coordinating center
  • Compares the current situation to the homeostatic
    norm
  • Can activate a mechanism to adjust situation
  • Regulator
  • A mechanism to restore normal balance

16
Example
  • During exercise, CO2 levels increase
  • Chemoreceptors in the arteries are stimulated
    (sensor)
  • They send a message to the medulla oblongata
    (coordinating center)
  • The medulla sends impulses to the intercostal
    muscles (regulator) to increase the rate of
    breathing to flush out excess CO2 from the body

17
Thermoregulation
  • Maintenance of body temperature within a range
    that allows cells to function efficiently
  • Different optimal temperatures and ranges exist
    for each animal

18
Thermoregulation and Invertebrates
  • Invertebrates, most fish, amphibians, and
    reptiles are also known as ECOTHERMS
  • These animals depend on air temperature to
    regulate metabolic rates.
  • Ex reptiles sun themselves on rocks or retreat
    to shaded areas to regulate their body temperature

19
Thermoregulation and Vertebrates
  • Mammals and birds are ENDOTHERMS
  • They are able to maintain a constant body
    temperature regardless of surroundings.
  • Thermoreceptors in the skin and in the
    hypothalamus of the brain monitor temperature
    changes in the environment and in the blood.

20
  • If an organism is too hot, it can cool down by
    using one or more of the following mechanisms
  • Vasodilation
  • Sweating
  • The evaporation of fluid from the skin requires
    energy, which is taken from body heat.
  • Decreased metabolism
  • Many biochemical reactions produce heat as a
    by-product
  • Behavioural adaptations

21
Vasodilation
  • Blood vessels in the skin dilate (become wider)
  • This increase blood flow to the skin.
  • Blood will bring heat.
  • Skin will become warmer and the heat will
    dissipate into the environment

22
(No Transcript)
23
Behavioural Adaptations
  • Birds bathing
  • Dessert Rodents retreat into burrows
  • Dogs dig holes and allow cool earth to absorb
    heat from belly

24
  • If an organism is too cold, it can warm up using
    one or more of the following mechanisms
  • Vasoconstriction
  • Shivering
  • Muscular contractions that produce heat a
    by-product
  • Increased metabolism
  • Biochemical reactions often produce heat as a
    by-product
  • Fluffing of hair or feathers
  • Thick layer of brown fat or blubber
  • Provides insulation, and generates heat
  • Special structures
  • Ex polar bears have hairs that can absorb UV
    light

25
Vasoconstriction
  • Blood vessels in the skin contract (get narrower)
  • This decreases blood flow to the skin
  • Less heat loss to the environment

26
(No Transcript)
27
Fluffing of hair or feathers
  • Increases the thickness of the insulating layer
    of air
  • Goosebumps
  • when you are cold, nerve message are carried to
    the muscle that surround the hair follicles in
    your skin causing the hair to stand up
  • The small bump made by the contraction of the
    muscle creates the goose bump
  • The hair traps warm air next to the surface of
    your skin and helps reduce heat loss

28
The Endocrine System
29
  • Endocrine System a system of glands that secrete
    hormones to regulate body function
  • HORMONES chemical messengers or regulators
  • - they are released by cells in one part of the
    body and affect cells in other parts of the body
    to speed up or slow down processes.
  • Endocrine Hormones are produced in endocrine
    glands and secreted directly in the blood and
    distributed by the circulatory system.

30
Makes hormones and regulates the pituitary gland
Pineal gland (makes serotonin which regulates
sleep patterns)
31
Endocrine Gland
32
How do Hormones Signal Cells?
  • Note Hormones do not affect ALL cells
  • Depends on whether or not that cell has a
    receptor for the particular hormone.
  • (TARGET CELLS are the cells hormones act on)
  • There are 2 types of hormones
  • 1. Steroid Hormones
  • 2. Protein Hormones (including polypeptides,
    glycoproteins, amines or tyrosine derivatives)

33
Steroid Hormones
  • made from cholesterol (lipid) Complex ring of C,
    H, and O
  • Soluble in fat but NOT water so can dissolve
    through cell membrane or nuclear membrane
  • Inside the cell they bind to receptor in the
    cytoplasm or nucleus to form the hormone-receptor
    complex

34
Steroid Hormones
  • The receptor-hormone complex can then switch
    certain genes on or off by promoting or
    inhibiting the transcription of genes in the
    nucleas
  • ex sex hormones estrogen, testosterone
  • ex cortisol
  • LIVER cortisol activates the genes for
    glucogenesis (the conversion of amino acids to
    glucose)
  • CELLS prevents the expression of the insulin
    receptor gene (preventing glucose storage)
  • PANCREAS inhibits the transcription of the
    insulin genes

35
Steroid Hormones
36
Steroid Hormones
SECRETORY CELL
HORMONE
TARGET CELL
RECEPTOR
37
Protein Hormones
  • Made of chains of amino acids or modified amino
    acids
  • Soluble in water but insoluble in fats (cant
    dissolve through cell membrane)
  • Ex insulin, growth hormone

38
Protein Hormones
  • The protein hormones attach to receptor sites on
    the cell membrane
  • The hormone-receptor complex leads to the release
    of a secondary messenger in the cell that can
    spread throughout the cell and relay messages
  • Ex of secondary messengers Ca2 and cyclic
    adenosine monophosphate (cyclic AMP)
  • Secondary messengers then activate enzymes in the
    cell.

39
Protein Hormones
40
Example
  • Ex epinephrine
  • Involved in the fight or flight response
  • Under a threat, an organism needs a supply of
    blood glucose as an energy source
  • In the liver, once cAMP is created, it activates
    enzymes which will activate the process of
    glycogen breakdown and inhibit glycogen synthesis
    (thereby increasing blood glucose levels)

41
Animations
  • http//highered.mheducation.com/sites/0072437316/s
    tudent_view0/chapter47/animations.html

42
Control Systems
  • The body relies on the nervous system and the
    endocrine system for control of organs and
    tissues
  • The nervous system allows the body to adjust
    quickly to environmental changes
  • The endocrine system is designed to maintain
    control over longer durations

43
Hypothalamus
  • The hypothalamus in the brain is part of both the
    nervous system and the endocrine system
  • As an endocrine gland it creates hormones that
    either
  • a) are stored in the (posterior) pituitary gland
  • b) control the release of hormones from the
    (anterior) pituitary gland

44
Pituitary Gland (The Master Gland)
  • master gland because it controls the other
    endocrine glands
  • (However, it is controlled by the hypothalamus)
  • Located at the base of the brain connected to
    the hypothalamus by a stalk
  • The pituitary produces and

    stores hormones
  • The hypothalamus stimulates
  • their release when necessary

45
(No Transcript)
46
Posterior Lobe
  • Stores and releases hormones that are actually
    made by the neurosecretory cells of the
    hypothalamus
  • The hormones travel from the hypothalamus to the
    pituitary via specialized nerve cells
  • They are stored in the pituitary and released
    into the blood when necessary
  • (The hypothalamus will send a nerve response to
    have the hormones released)
  • Ex ADH (antidiuretic hormone), oxytocin

47
Posterior Lobe
  • Ex ADH release
  • Hypothalamus creates ADH and stores it in
    pituitary gland
  • Osmoreceptors in hypothalamus recognize osmotic
    pressure (solute concentration of blood)
  • Impulses are sent to pituitary to increase or
    inhibit the release of ADH into blood stream
    accordingly

48
(No Transcript)
49
Anterior Lobe
  • Produces its own hormones
  • However, the hypothalamus regulate their release
    with inhibiting or releasing hormones made by the
    hypothalamus
  • The inhibiting and releasing hormones are
    transported to the anterior lobe of the pituitary
    via a portal vein
  • This stimulates the release of pituitary hormones
    which will travel through the blood to target
    cells

50
Anterior Lobe
  • Ex TSH and TRH
  • The anterior lobe produces and stores TSH
    (thyroid stimulating hormone)
  • TSH is released by the anterior lobe when the
    hypothalamus releases TRH (thyroid releasing
    hormone)

51
(No Transcript)
52
(No Transcript)
53
Hormone Target Organ Primary Function  
Thyroid Stimulating Hormone (TSH) Thyroid Gland Releases hormones made in the thyroid (such as thyroxine)
Adrenocorticotropic Hormone (ACTH) Adrenal Cortex Stimulates the release of hormones involved in the stress response (such as cortisol)
Somatotropin (STH) also known as Growth Hormone (GH) Most body cells Promotes growth
Follicle Stimulating Hormone (FSH) Gonads (ovaries and testes) Females stimulates follicle development in the ovaries Males Promotes the development of sperm cells in the testes
Luteinizing Hormone (LH) Gonads (ovaries and testes) Females stimulates ovulation and the formation of the corpus luteum Males stimulates the production of testosterone
Prolactin Mammary Glands Maintains milk production in lactating females
54
Posterior Pituitary Hormones
Hormone Target Organ Primary Function
Antidiuretic Hormone (ADH) kidneys Increases water reabsorption in the kidney
Oxytocin Uterus, mammary glands Initiates strong uterine contractions Triggers milk release in lactating females
55
Hormones that Affect Blood Sugar
56
Maintaining Blood Glucose
  • The pancreas is both an exocrine gland (producing
    digestive enzymes) and an endocrine gland
  • As an endocrine gland it produces 2 hormones
    essential to maintaining blood sugar levels
    within homeostatic ranges

57
  • The islets of Langerhans, are the cells in the
    pancreas that produce insulin and glucagon
  • a cells of Islets of Langerhans secrete glucagon
  • ß cells of Islets of Langerhans secrete insulin

58
Insulin
  • When blood glucose levels are too high, insulin
    is secreted.
  • It causes
  • the muscle cells to absorb more glucose (from the
    bloodstream)
  • hepatocytes and muscle cells to covert glucose
    to glycogen
  • In fat tissue (adipose tissue) , glucose to be
    converted into fat
  • Insulin is broken down by the cells it acts upon
    so it must be continuously secreted

59
Glucagon
  • Secreted by the pancreas when glucose levels are
    too low.
  • It travels throughout the body but its main
    target is the liver.
  • Causes hepatocytes to convert glycogen to glucose
    and release it to the blood

60
(No Transcript)
61
Diabetes Mellitus
  • Disorder in which a person does not produce
    enough insulin or in which a person does not
    react to insulin.
  • Can lead to hyperglycemia high blood glucose
  • Can cause nerve damage, retina damage, blood
    vessel damage, kidney failure, comas, and even
    death.

62
Signs of Diabetes
  • High, unregulated glucose levels means high
    levels of glucose in your urine
  • This will prevent water reabsorption in the
    kidneys
  • This leads to frequent urination
  • This leads to a person being constantly thirsty
    and craving sugary drinks

63
Type I Diabetes
  • Also called juvenile diabetes because diagnosed
    as a child
  • Individual doesnt make insulin, or makes
    insufficient levels of insulin.
  • Causes often by the body producing antibodies
    against insulin or ß cells of Islets of
    Langerhans the destruction of the ß cells of
    Islets of Langerhans
  • Treatment insulin injections, pancreas
    transplant, diet regulation

64
Type II Diabetes
  • Occurs later in life, as an adult
  • Insufficient amounts of insulin are produced or
    the body has become less sensitive to insulin
  • Causes obesity, age, family history, lifestyle
  • If the individual has a high glucose diet, their
    body will become desensitized to insulin.
  • Treatment regulated diet, exercise, medications
    to increase insulin production and lower blood
    glucose levels.

65
Diet (As Treatment)
  • Reduced sugar
  • Smaller more frequent meals
  • High-fibre foods (prevents sugar absorption)

66
Gestational Diabetes
  • Temporary Develops during pregnancy
  • Increased risk that the mother and child will
    develop (permanent) diabetes
About PowerShow.com