Regulation and Locomotion notes

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Transcript Regulation and Locomotion notes

Locomotion and
Skeletal System
 Functions
of bones:
 1. support and protection of the body
 2. anchorage sites for muscles
 3. leverage for movement
 4. production of blood cells in the bone marrow
 Cartilage provides support, flexibility, and
cushions joints
Muscular System
 Three
types of muscles
 1. smooth (visceral): involuntary
 2. cardiac: heart muscle, also involuntary
 3. skeletal (striated): voluntary
 Skeletal muscles pull on bones to move joints
 Extensor muscles extend (straighten) joints
 Flexor muscles flex (bend) joints
 Tendons: connect muscles to bones
 Ligaments: connect bones to bones
 Arthritis:
inflammation of the joints
 Tendonitis: inflammation of the tendons
Nervous System
 Nerves
send signals through the body
 Signals = impulses
 The nervous system has two parts:
 1. Central nervous system (CNS): brain and
spinal cord
 2. Peripheral nervous system (PNS): all nerves
outside the CNS
 The PNS is divided into two parts:
 1. Somatic nervous system: voluntary
 2. Autonomic nervous system: involuntary
 Nerves
are bundles of cells called neurons
 Impulses are passed from neuron to neuron
using chemicals called neurotransmitters
 Very fast
 Sensory neurons send impulses from body parts
to the CNS
 Motor neurons send impulses from the CNS to
the muscles
 Interneurons connect the sensory neurons to the
motor neurons
Axon terminals
Myelin sheath
Cell body
 Impulses
enter the neuron at the dendrites
 The impulse travels down the axon
 The myelin sheath insulates the axon
Just like rubber insulates wires
 When
the impulse reaches the axon terminals,
neurotransmitters are released
 Neurotransmitters carry the impulse to the
dendrites of the next neuron
Reflex Arc
reflex arc is a pathway over which impulses
 Receptors in the skin  sensory neurons 
interneurons in the spinal cord  motor neuron
 effector (muscle)
 Ex: when you touch a hot stove, the heat signal
travels to the neurons in the spinal cord, and a
message to move your hand gets relayed back
to your muscles
The Brain
 The
brain is a large mass of neurons
 It is responsible for controlling and coordinating
most of the activities of the body
 The brain has three main parts:
 1. Cerebrum: controls voluntary activities,
memory, thinking, and reasoning
 2. Cerebellum: coordinates muscle movements
and helps maintain balance
 3. Medulla: controls heartbeat, breathing, blood
pressure, and peristalsis
 Meningitis:
inflammation of the membranes that
surround the brain and spinal cord
 Stroke: when a blood clot blocks a blood vessel
in the brain
Causes cells to die
Endocrine System
 Composed
of mostly of glands
 Glands release hormones into the blood
 Hormones cause changes in certain cells
 Slower than the nervous system
Pituitary gland
Adrenal gland
 Hypothalamus:
part of the brain that controls
the pituitary gland
 Pituitary gland: “master gland” that regulates
many body parts
Makes growth-stimulating hormone (GSH), which
causes the bones to grow
Thyroid-stimulating hormone (TSH) makes the thyroid
make its hormone
Follicle-stimulating hormone (FSH) acts on the ovaries
and testes
 Thyroid:
regulates the rate of metabolism using
the hormone thyroxine
 Parathyroid: regulates the use of calcium using
the hormone parathormone
 Thymus: necessary for the immune system
 Adrenal glands: make adrenaline for the “fight
or flight” response
 Islets of Langerhans: cells in the pancreas that
control blood sugar levels
Insulin lowers blood sugar
Glucagon raises blood sugar
 Testes:
make testosterone for the development
of male secondary characteristics
 Ovaries: make estrogen for the development of
female secondary characteristics
Hormone Action
 Hormones
only affect certain cells
 All cells in the body have protein molecules on
the surface of the cell membrane
 These are called receptors
 Each type of cell has its own receptor shape
 Hormones can only affect cells whose receptors
match the shape of that hormone
Just like enzymes and substrates and antibodies and
 In
negative feedback, the release of one
hormone affects the production of another
 Ex: After a meal, blood sugar is high and insulin
is produced. This turns off glucagon production.
 Ex: After not eating for a while, blood sugar is
low and glucagon is produced. This turns off
insulin production.
 Negative
feedback also works to maintain other
aspects of homeostasis
 Ex: when your temperature drops too low, your
muscles contract rapidly (shivering) to generate
heat until your temperature goes back to normal
 Ex: when your temperature gets too high, you
sweat so that when the sweat evaporates, the
excess heat is removed from your skin
 The
body cannot make any insulin, or does not
make enough
 Blood sugar remains high, instead of going into
the cells to be turned into energy
 Type 1 diabetes occurs when the immune
system destroys the insulin-producing cells
Autoimmune disease
 This
is usually diagnosed in childhood and is
treated with insulin injections
 Type
2 diabetes occurs when the pancreas no
longer makes enough insulin or the body cells
cannot react to insulin
 May be caused by obesity, lack of exercise, or
 Can be managed with diet and medication
Nervous Vs. Endocrine
 Both
systems help maintain homeostasis
 The nervous system uses neurotransmitters
 The endocrine system uses hormones
 The nervous system is fast and responses are
 The endocrine system is slow and responses are