1. Turn in 2.3.1 Feedback Loop & completed Conclusion ?s
Keep Part III Body Graphic Organizer for 2.3.2
Endocrine System PPT
Activity Hormones Gone Wild Pt. 1
Groups of 4=Maniken Partner & Pair up with another Group

2. Pineal
Parathyroid
Pancreas
Pituitary
Adrenal
Thyroid
Thymus
Ovaries
Testes
10. Hypothalamus

3. THE ENDOCRINE SYSTEM

4. What is the Endocrine System?
Communication system for the body
Secretes hormones – chemical messengers
These hormones regulation of growth, metabolism, sexual development, and emotions
Internal balance of body systems = homeostasis by working with the nervous system
Specifically the hypothalamus

5. Endocrine Glands Ductless
Meaning: the hormone that is secreted goes into the blood stream directly to a target cell/tissue.
Major Endocrine Glands
Pituitary Gland
Hypothalamus
Thymus
Pineal Gland
Testes
Ovaries
Thyroid
Parathyroid
Adrenal Glands
Pancreas

7. Exocrine Glands They have ducts
carries secretions to external locations of the body
Examples
sweat glands
salivary glands
mammary glands
stomach
liver
pancreas

9. Hormones
HORMONES are chemical MESSENGERS that act on target cells or organs.

10. Classes of Hormones Steroid Hormones Amino Acid Derivative Hormones
Sex hormones – lipids made from cholesterol
Testosterone, Estrogen
Amino Acid Derivative Hormones
Derived from amino acids – tyrosine and tryptophan
Epinephrine
Peptide Hormones
Made of chains of amino acids
Most numerous
Insulin
Growth Hormone

11. Target Cells and Receptors
Target cells receive hormone (it binds to the cell membrane and enters the cell after it is recognized) and initiate a specific response.

12. FYI… Activity Information
Endocrine action: the hormone is distributed in blood and binds to distant target cells.
Paracrine action: the hormone acts locally by diffusing from its source to target cells in the neighborhood.
Autocrine action: the hormone acts on the same cell that produced it.

13. Endocrine Versus Nervous
Enable cells to communicate with others by using chemical messengers.
Endocrine system is slower than the nervous system because hormones must travel through the circulatory system to reach their target.

14. Nerve impulse Neuron transmits nerve impulse Neurotransmitter
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Nerve impulse
Neuron
transmits
nerve
impulse
Neurotransmitter
released into
synapse
Post-
synaptic
cell responds
(a)
Target cells
(cells with hormone
receptors) respond
to hormone
Glandular
cells secrete
hormone into
bloodstream
Bloodstream
Hormones have no
effect on other cells
(b) 14

16. Major Hormones

17. Pituitary Gland Often called the “master gland”
Controlled by the hypothalamus in the brain
Base of brain
Anterior and posterior pituitary lobes

19. Anterior Pituitary Hormone
Growth hormone (GH)- stimulates growth in childhood and is important for maintaining a healthy body composition
Problems with GH can result in too little growth or too much growth

20. The Alton Giant
Dwarfism

21. Thyroid Gland The thyroid hormones control your metabolism
Thyroxin (T4) & Tri- iodothyronine (T3) - both increase the rate at which cells release energy from carbohydrates
Calcitonin – regulates calcium in blood

22. Parathyroid Gland
Four tiny glands that help maintain calcium and phosphate levels
Parathyroid Hormone (PTH) - takes calcium from the bones to make it available in the blood

23. Adrenal Gland
Each adrenal gland is actually an organ located right on top of each kidney
Outer portion called adrenal cortex
Inner portion called adrenal medulla

24. Adrenal Cortex
Aldosterone – a mineralcorticoid, helps kidneys conserve sodium and excrete potassium, maintaining blood pressure
Cortisol – glucocortoid, keeps blood glucose levels stable
Adrenal Sex Hormones - androgens (male) and estrogens (female)

25. Pancreas
Large gland behind your stomach that helps the body to maintain healthy blood sugar (glucose) levels
Contains islands of cells called the Islets of Langerhans, which secrete glucagon and insulin

26. Pancreas Insulin- secreted when the blood sugar level is high
Glucogen- secreted when the blood sugar level is low
Both work together to keep blood sugar levels balanced

27. Pineal Gland located between the cerebral hemispheres
secretes melatonin- important for maintaining Circadian rhythms (light and dark activity)

28. Thymus Gland large in young children, gradually shrinks with age
secretes thymosins- important to immune function

29. Reproductive Gland
Ovaries- estrogen progesterone
Testes- testosterone

30. How Do We Maintain Homeostasis?
We maintain it with FEEDBACK LOOPS
We have receptors throughout our bodies; when levels are out of homeostasis; feedback loops are activated.
Mostly NEGATIVE FEEDBACK loops

31. There are 2 Types of Feedback: Negative and Positive
Negative Feedback - is called negative due to the fact that you are doing the OPPOSITE process. For example, if you body temperature is too high..negative feedback causes the temperature to DECREASE . Positive Feedback is a cascade and there is an increase in effect.

32. Negative Feedback Mechanisms
The net effect of the response to the stimulus is the SHUT OFF the original stimulus OR reduce its intensity.

33. Why This is Negative Feedback
Beta Cells of Pancreas
Release insulin in response to high sugar
Ultimately the INSULIN is turned off when sugar level returns to normal

34. Positive Feedback
The initial stimulus does NOT cause a switch to be “shut off”. Rather, a CASCADE of more ON switches in response to the initial response occurs.
Examples: Giving Birth and Blood Clotting

35. Positive Feedback: BIRTH
Cervix Dilates ( Initial STIMULUS)
Stimulates stretch receptors in cervix
These receptors stimulate Hypothamus (gland in brain)
Hypothamus “tells” posterior pituitary to release oxytocin.
Oxytocin acts on uterine muscles causing them to contract.
Muscle contractions force baby through cervix, stretching it. (REINFORCES ORIGINAL STIMULUS)

36. Homeostatic Control Mechanisms
Negative feedback summary:
Prevents sudden, severe changes in the body
Reduces the actions of the effectors
Corrects the set point
Causes opposite of bodily disruption to occur, i.e. the ‘negative’
Limits chaos in the body by creating stability
Most common type of feedback loop
Examples: body temperature, blood pressure & glucose regulation

37. Homeostatic Control Mechanisms
Positive feedback summary:
Increases (accelerates) the actions of the body
Produces more instability in the body
Produces more chaos in the body
There are only a few types necessary for our survival
Positive feedback mechanisms are short-lived
Controls only infrequent events that do not require continuous adjustments
Considered to be the uncommon loop
Examples: blood clotting and child birth