Anatomy & physiology: Muscular & Nervous systems
How do muscles produce movement?
By contracting in response to nervous stimulation
Muscle contraction results from the sliding together of ACTIN & MYOSIN FILAMENTS within the muscle cell or fiber.
Each muscle cell is made up of MYOFIBRILS,which in turn are made up of still smaller units called SARCOMERES.
What must be present in order for a muscle cell to contract?
Calcium & Adenosine triphosphate (ATP)
What causes the release of calcium ions from the sarcoplasmic reticulum?
Nervous stimulation from the motor neuron.
__1_ ions attach to inhibitory _2__ on the _3__ _4__ within the cell, moving them aside so that _5__-__5_ can form between _6__ and _7__ _8__. Using energy supplied by _9__, the _10__ slide together to produce _11__.
1. Calcium 9. ATP
2. Proteins 10. Filaments
3. Actin 11. Contraction
5. Cross bridges
Skeletal muscle which make up the muscular system, are also called
Voluntary muscles- because they are under conscious control.
Skeletal muscles work in pairs
The muscle that executes a given movement is the _1__, whereas the muscle that produces the opposite movement is the _2__. Other muscles known as _3__ may work in cooperation w/the prime mover.
1. Prime mover
Muscles can be classified according to the movements they elicit.
There are flexors & extensors.
reduce the angle at the joint.
increase the angle.
Draw a limb away from the midline (or body)
Return the limb back toward the body (adding to the body).
Diagram of the major contour muscles of the body. Study the names,notice their name is related to location & functions.
The Nervous system consists essentially of the
BRAIN, SPINAL CORD & THE NERVES
The Nervous system is broken into 2 categories the
CNS & the PNS
Central nervous system & Peripheral nervous system
CNS consists of
Brain & spinal cord
PNS consists of
all the nerves & their branches that transmit information to & from the CNS.
The Nervous system enables us to
perceive many of the changes that take place in our external & internal environments & to respond to those changes (seeing, hearing, tasting, smelling & touching are examples of perception).
The Nervous system also enables us to
think, reason, remember & carry out other abstract activities.
The Nervous system makes possible body movements by
skeletal muscles, by supplying them w/nerve impulses that cause contraction.
The Nervous system works closely with the
endocrine glands, correlating & intergrating body functions such as digestion & reproduction.
All actions of the nervous system depend on the transmission of nerve impulses over neurons, or nerve cells, the functional units of the nervous system.
What is the functional unit of the Nervous system?
Neuron (nerve cell).
The main parts of a neuron are the
cell body, axon & dendrites.
Dendrites transmit the impulse ___ the cell body.
The word dendrites have the letter "T" in it, *think of "T for to" like to the cell body."
Axons transmit the impulse ___ from the cell body.
*think of "A- A for Away from the cell body."
Sensory (afferent) neurons transmit nerve impulses ___ the CNS.
Motor (efferent) neurons transmit nerve impulses ___ from the CNS, toward the effector organs such as muscles, glands & digestive organs.
Motor (efferent neurons) transmit nerve impulses AWAY from the CNs towards
effector organs such as the muscles, glands & digestive organs.
The major parts of the brain are the
* associated w/movement & sensory input
* responsible for muscular coordination, including balance.
* Controls many vital funcitons such as respiration & heart rate.
Cerebrum is associated with
movement & sensory input
Cerebellum is responsible for
muscular coordination, including balance.
Controls many vital funcitons such as respiration & heart rate.
How long is the spinal cord?
Approximately 18 inches long.
The spinal cord extends from the base of the skull (foramen magnum) to the 1st or 2nd lumbar vertebrae (L1 or L2).
How many pairs of spinal nerves exit the spinal cord?
Simple (spinal) reflexes are those in which nerve impulses travel through the
spinal cord only and do not reach the brain.
Most reflex pathways involve impulses traveling
to & from the brain in ascending & descending tracts of the spinal cord.
Sensory impulses enter the _1__ of the spinal cord, & motor impulses leave through the _2__ of the spinal cord.
1. Dorsal horns
2. Ventral horns
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