REGULATION

* involves the control and coordination of all life functions
* use two main systems that use nervous and chemical control

NERVOUS SYSTEM: uses nervous contol (neurons); fast-acting, short-lasting
ENDOCRINE SYSTEM: uses chemical control (hormones); slow-acting, long-lasting

I. Human Nervous System--based on neurons

* remember stimulus-->response
* nerves are bundles of neurons all linked together (like a cable)
* there are 3 main types of nerves

A) Sensory Neurons

* pick up stimuli (changes in the environment) from receptors (sense organs--eyes, ears, nose, tongue, skin)
* transmit the impulse (electro-chemical signal) to the brain and spinal cord

B) Interneurons (Associative Neurons)

* relay the impulses from the sensory neurons to the nerves of effectors (muscles and glands)
* located mainly in the brain and spinal cord (which make up the Central Nervous System)

C) Motor Neurons

* carries the response impulses from the brain and spinal cord to the effectors


REMEMBER: The impulse is part electricity and part chemicals. The chemical parts of the impulse are different chemicals called neurotransmitters which travel in the spaces between neurons called synapses.

Human Regulation

see what drugs do to brain chemistry

II. The Central Nervous System

1) The Brain

* a large mass of neurons located in our cranial cavity (that is, our head!)
* has 3 major division, each having its own specific function:

A) Cerebrum

* the center of voluntary (stuff you can control) activity
* the messages from the receptors (brought to the brain by sensory neurons) are interpreted here
* motor activities are started here
* involves memory, thinking, reasoning, and habitual activities

B) Cerebellum

* coordinates motor activities and maintains balance

C) Medulla

* controls involuntary (automatic--things you cannot control) activities such as breathing, heartbeat, blood pressure, and peristalsis

2) Spinal Cord

* lies within the vertebrae of the spinal column (that is, each segment of our backbone) which protects it
* is continuous (is connected) with the brain
* coordinates activities between the brain and the other body structures
* is the center for REFLEX actions ("quick thinking")

* smaller nerves branch out of the spinal cord called (peripheral nerves) make up the Peripheral Nervous System

III. Never mind... but look at the Biolinks about drug effects!


IV. Malfunctions of the Nervous System

1) Cerebral Palsy

* a genetic (inborn) disease that affects speech and muscle centers of the brain

2) Meningtis

* an inflammation of the membranes surrounding the brain and spinal cord

3) Stroke

* a condition that results from a cerebral hemorrhage (internal bleeding in the brain) or a blood clot in the brain which may result in brain damage --the picture below shows the lack of oxygen (red region) in the brain during a stroke; the image is a CT scan--

4) Polio

* a viral disease of the central nervous system which may result in paralysis and is preventable through immunization

5) Spinal Cord Injuries

Human Regulation

a nice review of the brain; click on the appropriate buttons to start the tour
this guy has a 'Split Brain' personality! play this Flash game to see what I mean...
browse your way through a sometimes funny look at the effects of various drugs (and alcohol--which is also a drug) on humans; a must see for parents and students!
What do you mean there is no alcohol in this beer?
how addictive are some drugs? check out some of these unfortunate mice
the main page of the University of Utah's Genetic Science Learning Center that focuses on how addictive chemicals affect the brain

MOUSE PARTY

take a look at the actual chemical effects that are a result of various drug use by humans; another must see for parents!
see what are some of the signs of a stroke

V. The Endocrine System

* a means for chemical control
* consists of a number of glands which are located throughout the body
* the glands have secretions (mostly hormones) which affect certain tissues in the body
* hormones travel around the body dissolved in plasma (the blood--the circulatory system)

NEGATIVE FEEDBACK--THE WAY THESE GLANDS WORK

One hormone can cause another hormone to be produced (stimulated) or not produced (inhibited). This works like a thermostat. Say you set a thermostat to 70 degrees. When the temperature in the room goes below 70, the heater turns on. Once the temperature is 70, the heater turns off. This keeps the temperature in the room around 70 degrees. This type of control is exhibited by the hormones of human body to help maintain homeostasis.


VI. Organization of Endocrine Glands

A) Hypothalamus

* a small gland located within the brain
* even though it is part of the central nervous system, it has an endocrine job
* its secretions affect the...

B) Pituitary Gland

* also located in the brain
* produces a large amount of hormones, some are:

1) growth-stimulating hormone (GH)
* affects the growth of the long bones in the body (femur--thigh)

2) follicle-stimulating hormone (FSH)
* affects the ovary in females
* stimulates the egg cells to maturity

3) thyroid-stimulating hormone (TSH)
* stimulates another endocrine gland, the thyroid gland to produce its hormone, thyroxin

C) Thyroid Gland

* located in neck region (surrounding the trachea)
* produces thyroxin (contains iodine) which helps regulate metabolism and control normal physical and mental development

D) Parathyroid Gland

* found in the back of the thyroid gland
* produces parathormone which controls the levels of calcium in the body (bone and teeth growth)
* also is involved in proper nerve functioning and blood clotting

E) Adrenal Glands

* two small glands on the top of the kidney
* has two parts, the cortex and medulla

1) CORTEX
* secretes a cortisol (steroid hormone) that affects water balance and the conversion of fats and proteins to glucose

2) MEDULLA
* secretes adrenaline in times of emergencies; increases heart rate, breathing rate, and metabolism

F) The Islets of Langerhans

* tissues found in the pancreas
* produce the hormones insulin and glucagon (which have the opposite effects)

INSULIN-- promotes the storage of excess blood sugar (glucose--a monosaccharide) to a starch (glycogen--a polysaccharide) in the liver
(lowers blood sugar level)

GLUCAGON-- stimulates the conversion of the polysaccharide glycogen back to glucose (raises blood sugar level)

DIABETES:

* a disorder when the body has a hard time removing glucose from the blood and converting it to glycogen
* the body does not produce enough insulin

G) Gonads

MALE-- the testes, which secretes testosterone (influences the development of secondary sex characteristics)

FEMALE-- the ovaries, which secrete estrogen (influences the development of secondary sex characteristics)

Human Regulation

see how negative feedback works in this animation
see how insulin was discovered

VI. Organization of Endocrine Glands

A) Hypothalamus

* a small gland located within the brain
* even though it is part of the central nervous system, it has an endocrine job
* its secretions affect the...

B) Pituitary Gland

* also located in the brain
* produces a large amount of hormones, some are:

1) growth-stimulating hormone (GH)
* affects the growth of the long bones in the body (femur--thigh)

2) follicle-stimulating hormone (FSH)
* affects the ovary in females
* stimulates the egg cells to maturity

3) thyroid-stimulating hormone (TSH)
* stimulates another endocrine gland, the thyroid gland to produce its hormone, thyroxin

C) Thyroid Gland

* located in neck region (surrounding the trachea)
* produces thyroxin (contains iodine) which helps regulate metabolism and control normal physical and mental development

D) Parathyroid Gland

* found in the back of the thyroid gland
* produces parathormone which controls the levels of calcium in the body (bone and teeth growth)
* also is involved in proper nerve functioning and blood clotting

E) Adrenal Glands

* two small glands on the top of the kidney
* has two parts, the cortex and medulla

1) CORTEX
* secretes a cortisol (steroid hormone) that affects water balance and the conversion of fats and proteins to glucose

2) MEDULLA
* secretes adrenaline in times of emergencies; increases heart rate, breathing rate, and metabolism

F) The Islets of Langerhans

* tissues found in the pancreas
* produce the hormones insulin and glucagon (which have the opposite effects)

INSULIN-- promotes the storage of excess blood sugar (glucose--a monosaccharide) to a starch (glycogen--a polysaccharide) in the liver
(lowers blood sugar level)

GLUCAGON-- stimulates the conversion of the polysaccharide glycogen back to glucose (raises blood sugar level)

DIABETES:

* a disorder when the body has a hard time removing glucose from the blood and converting it to glycogen
* the body does not produce enough insulin

G) Gonads

MALE-- the testes, which secretes testosterone (influences the development of secondary sex characteristics)

FEMALE-- the ovaries, which secrete estrogen (influences the development of secondary sex characteristics)

Human Regulation

see how negative feedback works in this animation
see how insulin was discovered