Transcript 9b-9c-9i LN - Walnut High School

9b. Know how the nervous
system mediates communication
between different parts of the
body and the body’s interaction
with the environment.
9c. Know how feedback loops
in the nervous and endocrine
systems regulate conditions in
the body.
*9i. Know how hormones
(including digestive, reproductive,
osmoregulatory) provide internal
feedback mechanisms for
homeostasis at the cellular level
and in whole organisms.
Standard 9b & 9c Vocabulary
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Feedback Loops
Endocrine System
Negative Feedback
Regulation
Potassium Ion
Sodium Ion
Channel Ions
Impulse
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Neuron
Interneuron
Sensory Neuron
Motor Neuron
Brain
Reflex
Stimuli
Gray Matter
White Matter
Organization of the Body
• ___________
System
• Structures: Brain,
spinal cord, peripheral
nerves
• Function: Recognizes
and _____________
the body’s response
to changes in its
internal and external
environments
Organization of the Body
• ______________
System
• Structures:
Hypothalamus, pituitary,
thyroid, parathyroid,
adrenals, pancreas,
ovaries (in females),
testes (in males)
• Function: Controls
growth, development and
metabolism; maintains
________________
35-2 The Nervous System
– What are the functions of the nervous system?
• The nervous system controls and coordinates functions
throughout the body and responds to _______________ &
_____________ stimuli.
• Neurons
• The messages carried by the nervous system are electrical
signals called impulses.
• The cells that transmit these impulses are called
____________________.
Neurons
• Neurons are classified according to the
direction in which an impulse travels.
• ________________ neurons carry impulses from
the sense organs to the spinal cord and brain.
• _____________ neurons carry impulses from the
brain and spinal cord to muscles and glands.
• __________________ connect sensory and motor
neurons and carry impulses between them.
Neurons
• Structures of a Neuron
Nucleus
Dendrites
Axon
terminals
Cell body
Myelin sheath
Nodes
Axon
Neurons
• The largest part of a typical neuron is the
_________ __________.
• It contains the nucleus and much of the
cytoplasm.
Cell body
Neurons
• _____________ extend from the cell body
and carry impulses from the environment
toward the cell body.
Dendrites
Neurons
• The __________ is the long fiber that
carries impulses away from the cell body.
Axon
terminals
Axon
Neurons
• The axon ends in axon
_______________.
Axon
terminals
Axon
Neurons
• The axon is sometimes surrounded by an
insulating membrane called the __________
_______________.
• There are gaps in the myelin sheath, called
nodes, where the membrane is exposed.
• ____________ jump from one node to the next.
Myelin sheath
Nodes
39-1 The Endocrine System
– What is the function of the
endocrine system?
• The endocrine system is made up of
_____________ that release their
products into the bloodstream.
These products deliver messages
throughout the body.
• The _______________ released by
the endocrine system can affect
almost every cell in the body.
Hormones
• Hormones
• ____________________ are chemicals released in one part
of the body that travel through the bloodstream and affect the
activities of cells in other parts of the body.
• Hormones bind to specific chemical receptors on
cells.
• Cells that have receptors for a particular
hormone are called _______________
_______________.
• If a cell does not have ________________ or
the receptors do not respond to a hormone, that
hormone has no effect on it.
Glands
• Glands
• A gland is an organ that produces and releases a
secretion. There are two kinds of glands:
• ________________ glands release secretions
through ducts directly to the organs that use them.
• ________________ glands release their
secretions directly into the bloodstream.
Glands
•Hypothalamus
•The hypothalamus
makes hormones that
control the
____________ gland.
In addition, the
hypothalamus makes
hormones that are
stored in the pituitary
gland.
Glands
Pituitary gland
The pituitary gland
produces hormones that
regulate ________ of the
other endocrine glands.
Glands
• Parathyroid glands
• The parathyroid
glands release
parathyroid hormone,
which regulates the
level of ___________
in the blood.
Glands
• Thymus
• During childhood, the
thymus releases
thymosin, which
stimulates ________
development and
proper immune
response.
Glands
• Adrenal glands
• The adrenal glands
release
______________
and
norepinephrine,
which help the
body respond to
stress.
Glands
• Testis
• The testes produce
________________,
which is responsible
for sperm production
and the development
of male secondary
sex characteristics.
Glands
• Ovary
• Ovaries produce estrogen
and progesterone.
____________ is required
for the development of
female secondary sex
characteristics and for the
development of eggs.
Progesterone prepares
the uterus for a fertilized
egg.
Glands
• Pancreas
• The pancreas
produces
____________ and
glucagon, which
regulate the level of
_______________
in the blood.
Glands
• Thyroid
• The thyroid
produces thyroxine,
which regulates
______________
throughout the body.
Glands
• Pineal gland
• The pineal gland
releases
_____________,
which is involved in
rhythmic activities,
such as daily sleepwake cycles.
Hormone Action
• Hormone Action
• Hormones are classified as either
______________ or nonsteroids.
• Steroid hormones are produced from a lipid called
_____________________.
• Nonsteroid hormones include proteins, small
peptides, and modified amino acids.
Control of the Endocrine
System
• Control of the Endocrine System
– How does the endocrine system maintain
homeostasis?
• The endocrine system is regulated by feedback
mechanisms that function to maintain
____________________.
Control of the Endocrine
System
– Example: Controlling Metabolism
• Thyroxine, a hormone of the thyroid gland, affects
the activity of cells throughout the body, increasing
their rate of metabolism.
• A drop in thyroxine decreases the metabolic
activity of cells.
Control of the Endocrine
System
• If _______________ is low, the
hypothalamus secretes thyrotropinreleasing hormone (TRH), which
stimulates the anterior pituitary to secrete
thyroid-stimulating hormone (TSH).
• TSH stimulates the release of thyroxine.
• High levels of thyroxine in the blood inhibit
secretion of _______ & _________,
which stops the release of additional
thyroxine.
Control of the Endocrine
System
• Controlling
Metabolism
Control of the Endocrine System
• The hypothalamus is also sensitive to
________________.
• If body temperature drops, it produces
extra TRH.
• TSH is released, which causes the release
of more thyroxine.
• Thyroxine increases _____________
consumption and cellular metabolism.
• Increased metabolic activity maintains a
core temperature.
Complementary Hormone
Action
• Complementary Hormone Action
• Sometimes two hormones with opposite effects act to
regulate part of the body’s internal environment.
• Such a complementary system regulates the level of calcium
ions in the bloodstream.
• Two hormones that regulate calcium
concentration are calcitonin and parathyroid
hormone (______).
• Calcitonin decreases the level of ___________
in the blood, while PTH increases it.
Complementary Hormone
Action
• If calcium levels are too high, the thyroid
secretes calcitonin.
• Calcitonin signals the ____________ to
reabsorb less calcium.
• Calcitonin also reduces the amount of
calcium absorbed in the intestines and
stimulates calcium deposition in the
bones.
Complementary Hormone
Action
• If calcium levels drop too low, PTH is
released by the parathyroids.
• PTH, with _________________,
stimulates the intestine to absorb more
calcium from food.
• PTH also causes the kidneys to retain
calcium, and it stimulates bone cells to
release calcium stored in bone tissue into
the bloodstream.
39-2 Human Endocrine Glands
• The endocrine glands are scattered
throughout the body.
• The human endocrine system regulates a
variety of ______________.
• Any improper functioning of an endocrine
gland may result in a disease or a
disorder.
Pituitary Gland
• Pituitary Gland
– What is the function of the pituitary gland?
• The pituitary gland secretes nine hormones that
directly regulate many body functions and controls
the actions of several other endocrine glands.
– The _______________ ________ is a structure at the
base of the skull.
– The gland is divided into two parts: the anterior pituitary
and the posterior pituitary.
Pituitary Gland
• The Pituitary Gland
Hypothalamus
Anterior
pituitary
Posterior
pituitary
Pituitary
gland
Hypothalamus
• Hypothalamus
– What is the function of the hypothalamus?
• The hypothalamus is the part of the _________
attached to the posterior pituitary.
• The hypothalamus controls the secretions of the
pituitary gland.
Hypothalamus
Hypothalamus
Pituitary gland
Hypothalamus
• The hypothalamus is influenced by hormone
levels in the ___________ and by sensory
information.
• Interactions between the nervous system and
the endocrine system take place at the
hypothalamus.
• The close connection between the
hypothalamus and the pituitary gland means that
the nervous and endocrine systems act together
to coordinate body activities.
Adrenal Glands
• Adrenal Glands
– What is the function of the adrenal glands?
• The adrenal glands are two pyramid-shaped
structures that sit on top of the kidneys, one
gland on each kidney.
• The adrenal glands release hormones that help the
body prepare for and deal with _______________.
Adrenal Glands
Adrenal gland
Kidney
Adrenal Glands
• An adrenal gland
has an outer part
called the
___________
____________
and an inner part
called the
adrenal medulla.
Adrenal
cortex
Adrenal
medulla
Adrenal Glands
– Adrenal Cortex
• The adrenal cortex produces over 24 steroid
hormones.
• The hormone aldosterone regulates
_______________ of sodium ions and the
excretion of potassium ions by the kidneys.
• The hormone cortisol controls the rate of
metabolism of __________________, _________,
_________________ & _________________.
Adrenal Glands
– Adrenal Medulla
• The release of hormones from the adrenal medulla prepares
the body for __________-_________ activities.
• The two hormones released by the adrenal medulla are
epinephrine and norepinephrine.
• Epinephrine and norepinephrine:
• increase heart rate, blood pressure, and blood flow to the
muscles.
• cause air passageways to open wider, allowing for an
increased intake of oxygen.
• stimulate the release of extra glucose into the blood to help
produce a sudden burst of energy.
Pancreas
• Pancreas
– What is the function of the pancreas?
• The pancreas has both exocrine and endocrine
functions.
• It is a digestive gland whose secretions break
down food.
• It produces insulin and glucagon.
» Insulin and glucagon help to keep the level of
________________ in the blood stable.
Pancreas
• Insulin stimulates cells in the
___________ and muscles to remove
sugar from the blood and store it as
glycogen or fat.
• _______________ stimulates the liver to
break down glycogen and release glucose
back into the blood.
Pancreas
– Maintaining Blood Sugar Levels
• When glucose levels rise, the pancreas releases insulin.
• Insulin stimulates cells to take glucose out of the
bloodstream.
– _____________ taken out of circulation is stored as
_______________ in the liver and skeletal muscles.
– In fat tissue, glucose is converted to lipids.
– When blood glucose level drops, glucagon is released
from the pancreas.
Pancreas
• Glucagon stimulates liver cells and
skeletal muscles to break down glycogen
and increase glucose levels.
• It causes fat cells to break down fats for
production of carbohydrates.
• This makes more chemical
_____________ available and helps raise
the blood glucose level back to normal.
Summary
• Organisms maintain a constant internal
environment, even when conditions
outside the body change. The nervous
system _______________ body
conditions, such as temperature, and
signals endocrine glands, such as the
hypothalamus, to release chemicals that
help keep _________ conditions constant.
Summary
• Hormones are chemicals that are released
in one part of the body and affect another
part of the body. Hormones control body
conditions such as temperature, and thus
they help organisms maintain a constant
internal environment. Feedback
mechanisms work to regulate the activity
of the body and help maintain
homeostasis.