Transcript Chapter 9- Endocrine System

Chemical Regulation
Chemical Control in Plants:
 Hormones
–
–
–
–
allow for
Growth
Reproduction
Tropisms
Hormones found in roots, stems, and seeds
Role of Hormones
 Auxin:
– a hormone that allows for cell division and
growth.
– An unequal distribution of auxin, causes a
tropism.
 Tropism:
– Response to stimulus.
– Ex. Light phototropism
Water hydrotropism
Tropism in plants
Phototropism
 Less
auxin on light side
 More auxin on dark side
 Positive phototropism
– (grows towards light)
Aim: What is the function of the
human endocrine system?
Chapter 15- Endocrine System
 Composed
of glands located throughout
the body that secrete hormones
 Endocrine Glands:
– Produce hormones
 Chemical
messengers
 Specific- affect different target cells of the body
– These glands are ductless.
Human Endocrine System
 Exocrine
Glands: contain ducts which
secretions pass through. Ex) Salivary
glands
 Endocrine Glands:Ductless.
– Hormones are secreted directly
into the bloodstream.
– The hormones maintain
homeostasisREGULATION.
Nervous System vs. Endocrine System
Nervous System
Endocrine System
Maintain Homeostasis
Chemical
Neurotransmitters
Fast Response
Quick Response
Maintain Homeostasis
Chemical Hormones
Slow Response
Lasts Longer
Aim: What are some of
the glands of the Human
Endocrine System?
Hypothalamus:
Area of the brain that connects the N.S. to the
endocrine system.
 Stimulates the pituitary gland.

Types of Glands:
 Pituitary
– “master gland”
– produces hormones that turn on other glands.
– Location: within brain
– Hormones Secreted:
Growth Hormone
Thyroid Stimulating Hormone (TSH)
Follicle Stimulating Hormone (FSH)
Luteinizing Hormone (LH)
Hypothalamus
Pituitary Hormones:
Thyroid stimulating Hormone- TSH
Stimulates the thyroid gland to produce
thyroxin.
 Follicle stimulating Hormone- FSH
Stimulates the ovaries and testes.
 Growth Hormone- GH
Increases growth of bones and muscles.
 Leutinizing Hormone- LH
Stimulates ovulation to occur in females.

Thyroid gland
Thyroid Gland
 Thyroxin
Hormone
 Contains iodine
 Regulates metabolism
 Location: In Neck
Parathyroid gland
Parathyroid Glands
Parathormone
 Regulates calcium metabolism
 Location: Small pairs of glands in neck

Adrenal gland
Adrenal Glands
Adrenaline (epinephrine) Hormone
 Helps the body in emergency situations
 Increases- heartbeat, respiration, blood sugar
levels.(Adrenaline Rush)

Pancreas: Islets of Langerhans
Location: group of cells located in the pancreas.
 Insulin Hormone
 Is needed to allow sugar to enter our cells.
 Lowers blood sugar (glucose) levels.
 When does insulin get produced in our bodies?
 After we eat b/c the sugar needs to go into our
cells.

Pancreas
Pancreas-Islets of Langerhans
Glucagon Hormone
 Opposite of insulin
 Increases blood sugar (glucose) levels.
 Causes sugar to be released from the liver when
blood sugar levels are too low.
 When is glucagon produced in our bodies?
 When we skip a meal- blood sugar is too low.

Testes
 Gonads-
Sex Glands
 In the gonads, sex cells develop into
gametes (sperm cells and egg cells).
 Male gonads: Testes
– Testosterone Hormone
– Develops secondary sex characteristics
– Deep voice, facial hair.
Ovaries
 Female
gonads: Ovaries
 Estrogen Hormone
– Develops secondary sex characteristics
– Broad hips, hair growth
– Regulates menstrual cycle
 Progesterone
Hormone
– Regulates menstrual cycle
Testes/ Ovaries
Regulation of Hormone
Secretion
Hormones are not secreted at a constant rate.
 Hormone secretion varies with the body’s needs
 This is accomplished by FEEDBACK.
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Negative feedback:
– Opposes original change
– Most common - maintains homeostasis
1.
2.
3.
4.

Negative Feedback –
Mechanism that maintains
homeostasis
High Blood Sugar
Pancreas secretes insulin
Blood Sugar lowers to homeostasis
Pancreas stops secreting insulin
Negative Feedback regulates
homeostasis like a thermostat regulates
temperature
Malfunctions of the Endocrine
System

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Diabetes:
Caused by an insulin deficiency (Pancreas doesn’t make enough)
Results in an elevated blood sugar level.
To manage this, medication or injections of insulin must be taken
 Goiter:
 Enlargement
of the thyroid gland.
 Caused by a hyposecretion of thyroxin.
 Also caused by an iodine deficiency.
Giantism
Dwarfism
Dwarfism
How Hormones Work
 Hormones
are specific!!!!
 Hormone and target cell receptors fit
together like a “lock and key”