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REGULATION CHEMICAL REGULATION –CHAPTER 16. Chemical vs Nervous Regulation Body systems never rest...
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Transcript of REGULATION CHEMICAL REGULATION –CHAPTER 16. Chemical vs Nervous Regulation Body systems never rest...
REGULATION
CHEMICAL REGULATION –CHAPTER 16
Chemical vs Nervous Regulation
Body systems never rest – make constant adjustments to maintain homeostasis Nervous system and endocrine system Endocrine system releases chemicals into the
blood stream and regulates metabolism, growth, reproduction
Chemical regulation is slower than impulse regulation
Chemical regulation results lasts longer than nervous regulation
Glands
Glands are made of epithelial cells that secrete substances needed by the body
Exocrine glands have ducts that carry secretions to where they are needed
Endocrine glands (ductless glands) secrete directly into the blood stream Make up the endocrine system Secrete hormones that travel in the blood stream Controls homeostasis, metabolism, growth,
reproduction
Exocrine glands have ducts that carry secretions to where they are needed
Endocrine glands (ductless glands) secrete directly into the blood stream
Hormones
Chemical messengers – where secreted is not where it is used
Target tissue is the specific tissue that recognizes a specific hormone
Hormone stimulates target tissue to increase, decrease, stop or start activities Hormones do not act directly on the target
tissue but change a cellular process that affects the target tissue
Target tissue is the specific tissue that recognizes a specific hormone
Hormone stimulates target tissue to increase, decrease, stop or start activities
Hormones
Two types of hormones
Protein type (made of amino acids) cannot pass through the cell membrane (ex: insulin)
Steroid type (lipid-like) can pass through the cell membrane (ie: estrogen)
Hormones
Protein type (made of amino acids) cannot pass through the cell membrane (ex: insulin)
Hormones
Steroid type (lipid-like) can pass through the cell membrane (ie: estrogen)
The Regulation of Hormones
The rate of secretion varies with the needs of the body
Chemical stimulation regulates secretions and overlaps with the nervous system
Chemical regulation is accomplished by feedback Positive feedback – reinforces the original change Negative feedback – opposes the original change Negative feedback usually maintains homeostasis
Mechanisms of Hormone Action
Hormones are in the blood and enter all organs but are only recognized by the target tissues
HOW?
One-messenger Model
Steroid hormones Enters all cells of the
body but only the target tissue has receptor proteins that react with the hormone and form an active factor. The active factor produces the hormone effect.
Two-messenger Model
Protein-type hormones
Cannot pass through the cell membrane – specific receptors on the outer surface of the target cell membranes that react and activate enzymes in the membranes that act as a second messenger.
Add the following table to the bottom of page 20 in your
packet
Compare Chemical Regulation vs Nervous Regulation
Chemical Regulation Nervous Regulation
Both systems work together to maintain homeostasis
Reacts more slowly Reacts more quickly
Effects last longer Effects are short term
Chemical messengersElectrochemical
messengersMessengers (hormones) travel all over the body in
the blood (circulation)
Messengers are directed to a specific
area (nerve pathways)
Turn to the diagram on page 26 in your packet
HUMAN ENDOCRINEPineal
Testes
Pancreas
Adrenals
Thymus
Parathyroids
Thyroid
Pituitary
Hypothalamus
Ovary
Turn to page 28 in your packetFollow along with the notes
Pituitary Gland Known as the Master Gland Controls the release of
hormones from many other endocrine glands
Connected to the hypothalamus which Controls the release of
hormones from the pituitary Receives information from the
nervous system Stimulates the pituitary to
release hormones
ANTERIOR PITUITARY
1. Thyroid-stimulating hormone (TSH) Stimulates the production and release of thyroxin from the
thyroid2. Adrenocorticotropic hormone (ACTH)
Stimulates the production and release of hormones from the adrenal glands
3. Growth hormone (GH) Indirectly affects bone and cartilage growth Directly affects cellular metabolism
4. Follicle-stimulating hormone (FSH) Stimulates development of eggs (female – ovaries) Stimulates production of sperm (males – testes)
5. Luteinizing hormone (LH) Stimulates the release of eggs from the ovaries Controls production of sex hormones in males and females
6. Prolactin Stimulates secretion of milk after child birth
POSTERIOR PITUITARY
1. Connected to the hypothalamus
2. Oxytocis Stimulates contraction of the uterus
during child birth
3. VasopressinControls reabsorption of water by the
nephrons in the kidneys
THYROID
Located under the larynx –
in front of the trachea Thyroxin
Regulates the rate of metabolism
Calcitonin Regulates the blood’s calcium
level
PARATHYROID GLANDS
Four tiny glands in the back of the thyroid
1. Parathyroid hormone Regulates calcium and
phosphate metabolism hypersecretion –
removes Ca from the bones – osteoporosis
hyposecretion – lowers the blood’s Ca level – tetany
THE ADRENAL GLANDS
Located on the kidneys Helps the body deal with stress (fight or flight
response)
THE ADRENAL GLANDS
Adrenal medulla (inner layer of the adrenal gland) Epinephrine or adrenalin (80%) Norepinepherine or noradrenalin (20%)
Regulates the fight or flight response Responds to fear, anger, pain, exertion Causes increased rate of metabolism and
increased release of glucose (increases heart rate, blood pressure, breathing rate, blood clotting, and sweating)
THE ADRENAL GLANDS
Adrenal cortex (outer layer of the adrenal gland)
1. Cortisol Controls metabolism of carbohydrates,
proteins, and fats
2. Cortisone Counteracts allergies
3. Aldosterone Regulates mineral balance in the blood
PANCREAS
Is both an exocrine and endocrine gland!!
PANCREAS
Exocrine Secretes digestive juices through the
pancreatic duct to the small intestines
PANCREAS
Endocrine –secretions from the islets of Langerhans
1. Alpha cells Secretes glucagon Raises the blood sugar (glucose) levels
2. Beta cells Secretes insulin Lowers blood sugar (glucose) levels
When the islets of Langerhans fail to produce insulin – diabetes mellitus results
THE GONADS (sex glands)
Ovaries (female)
1. Estrogen Stimulates the development
of female reproduction system
Stimulates the development of secondary female sex characteristics
2. Progesterone Regulates female menstrual
cycle
THE GONADS (sex glands)
Testes (male)
1. Testosterone Stimulates the development
of male reproduction system
Stimulates the development of secondary male sex characteristics
Turn to page 22 in your packet
What is Regulation?
All the activities that help maintain an organism’s homeostasis
Compare Nervous System vs Endocrine System
The nervous system: Responds quickly Short lasting
The endocrine system: Responds more slowly Longer lasting
Compare Endocrine Glands vs Exocrine System
Endocrine glands (ductless glands) secrete hormones which travel to target
tissues through the blood examples = ovaries, thyroid
Exocrine glands have ducts or tubes that carry secretions to
the target organ example = digestive glands (pancreas)
Compare Two Types of Hormones
Steroid small and lipid-like can pass through the cell membrane example = estrogen one messenger model
enters many cells effects only cells with specific receptor
proteins
Compare Two Types of Hormones
Protein-type made of amino acids – large molecules cannot pass through the cell membrane example = insulin two messenger model
target cells have receptor proteins on the cell membrane surface
hormone and receptor combine – release enzyme into the cell that acts as a second messenger
Check out the diagrams on page 23B in your packet
(one and two messenger models)
Check out the diagram on page 23A in your packet
(positive and negative feedback)
Regulation of Hormone Secretion
Feedback = the level of one hormone inhibits or stimulates the production of another hormone
1. Positive feedback = reinforces the original change
2. Negative feedback = opposes the original change
Turn to page 27 in your packet
Turn to page 29 in your packet
RECEIVES SENSORY INPUT RECEIVES SENSORY INPUT
HYPOTHALAMUS
•Part of the brain•Receives sensory input
•Controls the release of hormones in the pituitary (releasing factors)
PITUTARY GLAND “Master Gland”
secretes secretes TSH ACTH
(thyrotrophic stimulating hormone) (adrenocorticotrophic hormone)
secretes cortisol
(controls the metabolism of carbohydrates, proteins, and
fats)
ADRENAL CORTEX
•An increased rate of metabolism will inhibit the hypothalamus
•An decreased rate of metabolism will stimulate the hypothalamus
THYROID
secretes thyroxin(controls the rate of metabolism)
Endocrine Disorders and Diseases
Anterior PituitaryGrowth Hormone
HYPERSECRETION HYPOSECRETION
Gigantism (child onset)Body proportional
Dwarfism (body proportional)
Acromegaly (adult onset)Enlarged hands, feet and facial features
Gigantism (child onset)Body proportional
Anterior Pituitary - Growth HormoneHYPERSECRETION
Acromegaly (adult onset)Enlarged hands, feet and facial features
Anterior Pituitary - Growth HormoneHYPERSECRETION
Dwarfism (body proportional)
Anterior Pituitary - Growth HormoneHYPOSECRETION
Adrenal Cortexcortisol (controls metabolism)
HYPERSECRETION HYPOSECRETION
Cushing’s Disease Fat deposits upper body, puffy
face, excess facial hair
Addison’s DiseaseSluggish, weight loss, weakness
John F. Kennedy had Addison‘s Disease
Thyroidthyroxin (rate of metabolism)
HYPERSECRETION HYPOSECRETION
HyperthyroidismNervous, irritable, eyes may
protrude
HypothyroidismADULT onset: Sluggish, tired, weight gainCHILD onset: cretinism – dwarfism (body not proportional) and mental retardation
Thyroid
Thyroxin contains iodine Deficiency of iodine causes a goiter
Pancreassecretes insulin for glucose metabolism
HYPERSECRETION HYPOSECRETIONDiabetic Shock
Cold sweat, confusion, In extreme cases:
unconsciousness, coma, death
Uncontrolled diabetesDehydration, weight loss, thirst,
irritability
Remember: the pancreas is both an exocrine gland (digestive juices) and an endocrine gland (insulin and glucagon for controlling blood sugar levels.
Review the answers to the worksheets on pages 24-25 in your
packet
Please turn to page 21 in your packet
Did you know that plants have hormones, too?
Plant Hormones Chemical messengers Produced in tips of roots and stems (meristem region) Three kinds1. Auxins = hormones that affect growth
Stimulate or slow growth Cause cells to lengthen and differentiate Affects abscission (dropping off of leaves, fruit,
flowers)2. Gibberellins
Distributed evenly through out the plant tissue Affects stem growth and fruit size
3. Cytokinins stimulate cell division and growth during seed
germination
Auxins and Tropism
Tropism = growth of a plant in a specific direction in response to a stimulus Toward the stimulus – positive
tropism Away from the stimulus – negative
tropism Kinds of tropism
phototropism = light geotropism = gravity thigmotropism = touch hydrotropism = water
Nastic Movements
Plant movement in response to a stimulus, but independent of the direction of the stimulus Prayer plant – leaves
collapse due to loss of turgor (water pressure)
Venus fly trap
Photoperiodism
Response of a plant in response to changes in the length of a day
Not time of light that determines flowering, but the number of dark hours1) Short-day (long night) plants bloom in spring,
late summer2) Long-day (short night) plants bloom in summer3) Day-neutral plants are not affected by light
hours Affected by pigment phytochrome