chapter 10. regulating body function working closely with your nervous system is the endocrine...
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Regulating Body FunctionWorking closely with
your nervous system is the endocrine system, a chemical communication system that regulate many body functions.
Exocrine vs EndocrineExocrine Glands Endocrinesecrete their products
into ducts that empty onto a surface or into a cavity.
Ex: Sweat glands and salivary glands
Ductless glands. They secrete
chemicals (hormones) into intracellular spaces.
NOT
Regulating Body FunctionA gland is a group of cells, or an organ, that
secretes a chemical substance. The endocrine glands secrete chemicals
called hormones directly into the bloodstream.
The blood carries the hormones directly to the tissue they are targeted to affect.
Some hormones are produced continuously, while others are produced only at certain times.
Regulation of Hormone SecretionNegative Feedback Positive FeedbackHomeostatic control
mechanism that reverses what is happening in the body
More common than positive feedback. Ex: Insulin, Body
Temperature, Blood Pressure
Amplifies changes rather than reverses them. Ex: Labor – amplified
contractions.
Mechanisms of Hormone ActionNonsteroid Hormones
Steroid HormonesSecond messenger
mechanism: nonsteroid hormones serve as 1st messenger between gland and cells; Another molecule will then act as a 2nd messenger providing communication within the target cell
Lipid-solubleCan pass through cell
membrane of target cellBind with receptors on
the nucleus and act on DNA
PituitaryThe pituitary gland at the base of the brain
is a gland that signals other endocrine glands to produce hormones when needed.
It is also known as the “Master Gland” and is located at the base of the brain.
It secretes several hormones. These regulate the thyroid gland, adrenal
glands, and kidneys- plus your growth and development. It produces growth hormones.
PituitaryAnterior PosteriorTSH
Thyroid stimulating
ACTH Adrenocorticotropic
FSH Follicle-stimulating
LH luteinizing
GH growth
Prolactin
ADHAnti-duretic
Oxytocin
HypothalamusThe
hypothalamus is a vital neuroendocrine and autonomic control center beneath the thalamus.
Secretes:Releasing
hormones Anterior pituitary
Inhibiting hormones Posterior pituitary
ParathyroidThe parathyroid
glands direct the distribution of certain minerals in your body.
Increase Ca+ in blood
SecretesParathyroid
hormone or PTH
PancreasThe pancreas is part of two body systems-
the digestive system and the endocrine system.
It is located behind the stomach and supplies the small intestine with digestive juice.
It produces insulin and contains small clusters of cells called the islets of Langerhans, which control blood sugar levels.
It produces insulin.
ThymusThe thymus gland
is located in the mediastinum.
It is a vital part of the body’s immune system.
Produces thymosin
ThyroidThe thyroid gland
is located where the larynx and trachea meet.
It regulates the chemical reactions of nutrients in the cells.
It produces thyroxine.
AdrenalThe adrenal glands are located on your
kidneys. They secrete hormones that help the body
maintain its levels of sodium and water, aid the digestive process, and control your body’s response to emergencies.
It produces adrenaline.
The Body’s Response to StressWhen your brain
recognizes a stressful situation, your adrenal glands responds by releasing the hormone adrenaline. This hormone prepares your body to respond to stress.
ReproductiveDuring adolescence, the endocrine system
plays an important role in growth and development.
OvariesThe ovaries are the
female reproductive glands.
They control the development of secondary sex characteristics during adolescence.
It produces estrogen.
PlacentaThe placenta anchors the developing fetus to
the uterus and provides a “bridge” for the the exchange of nutrients and waste products between the mother and the developing baby.
TestesThe testes are the
male reproductive glands.
They control the development of secondary sex characteristics during adolescence.
It produces testosterone.
Secretions of HormonesHyposecretion HypersecretionProduction of too little
hormone by a diseased gland
Production of too much hormone by a diseased gland
DiabetesDiabetes mellitus is a disease that may be
caused by inadequate insulin production by the pancreas.
Symptoms include: lack of energy weight loss extreme thirst frequent urination
THYROIDHYPOTHRYOIDISM HYPERTHYROIDISMUnderactive thyroid
gland can cause a dull facial expression, hoarse voice, facial puffiness, coarse, dry skin and hair, and weight gain.
Goiter- caused by low dietary iodine intake
Cretinsim- when hyposecretion occurs in infants/toddlers
Overactive thyroid gland produces symptoms that may include protrusion of eyeballs, warm, moist skin, trembling hands, nervousness, increased sweating, disturbed sleep, and weight loss.
Growth Hormonehyposecretion hypersecretionDwarfisim Gigantism
Acromegaly results when GH is secreted too much after adolescents.
ParathyroidParathyroid hormone (PTH) and vitamin D
help manage calcium balance in the bodyCalcium is important to many body functions,
including:Bone formationHormone releaseMuscle contractionNerve and brain function