Introduction Flashcards
Regional anatomy
is the study of the interrelationships of all of the structures in a specific body region, such as the abdomen.
systemic anatomy
is the study of the structures that make up a discrete body system
physiology
is the scientific study of the chemistry and physics of the structures of the body and the ways in which they work together to support the functions of life
Homeostasis
is the state of steady internal conditions maintained by living things.
organ systems each have different functions
organization, metabolism, responsiveness, movement, development, and reproduction.
6 environments related to an organism
Metabolism
the sum of all anabolic and catabolic reactions that take place in the body.
Catabolisim
Release energy
Anabolism
Requires energy
Responsiveness
the ability of an organism to adjust to changes in its internal and external environments.
An example of responsiveness
moving toward sources of food and water and away from perceived dangers
Development
all of the changes the body goes through in life
differentiation
unspecialized cells become specialized
Growth
generally the increase in body size.
All multicellular organisms, grow by :
increasing the number of existing cells, increasing the amount of non-cellular material around cells (such as mineral deposits in bone), and, within very narrow limits, increasing the size of existing cells.
Reproduction
the formation of a new organism from parent organisms
Requirements of life
Oxygen
Nutrients
Narrow range of temperature
Narrow range of atmospheric pressure
Oxygen
key component of the chemical reactions that keep the body alive, including the reactions that produce ATP.
Nutrients
substances in foods and beverages that are essential to human survival.
The three basic classes of nutrients
water
the energy-yielding and body-building nutrients (lipids, carbs, proteins)
the micronutrients (vitamins and minerals).
Narrow range of temperature
The chemical reactions upon which the body depends can only take place within a narrow range of body temperature
just above 37°C (98.6°F)
Narrow range of atmospheric pressure
Atmospheric pressure is pressure exerted by the mixture of gases (primarily nitrogen and oxygen) in the Earth’s atmosphere.
This pressure keeps gases within the body
affects one’s ability to breathe—that is, to take in oxygen and release carbon dioxide.
Homeostasis
Maintaining homeostasis requires that the body continuously monitor its internal conditions
body temperature, blood pressure, certain nutrients etc.p. J v
The three types of muscle include
skeletal, smooth, and cardiac muscle
make up of the muscular system
Skeletal muscles, along with other types of muscle tissue, nervous tissue, blood, and other connective tissues,
fascia
layers of fibrous connective tissue
Individual skeletal muscles are separated from other muscles and held in position by
Fascia
Fascia
surrounds every muscle and may form cordlike tendons beyond each muscle’s end
aponeuroses
Broad sheets of fibers that may attach to bones or to the coverings of other muscles
epimysium
Surround muscles closely
Perimysium
Separates the muscle into small compartments
fascicles
Found inside perimysium
Made up of bundles of skeletal muscle fibers
endomysium
Inside fascicles
Contain muscle fibers
skeletal muscle fiber
A single cell that contracts in response to stimulation and relaxes when the stimulation ceases
sarcolemma
The cell membrane of a Muscle cell
sarcoplasm
cytoplasm
sarcoplasm is made up of
many threadlike myofibrils arranged in a parallel fashion to each other
Myofibrils
have thick protein filaments composed of myosin, and thin protein filaments mostly composed of actin
myosin
thick protein filaments
actin
thin protein filaments
striations
areas of alternating, colored bands of skeletal muscle fiber
sarcomeres
The repeating patterns of striation units
that appear along each muscle fiber
two main parts of the striation pattern
light bands (I bands)
dark bands (A bands)
light bands (I bands)
made up of thin filaments of actin attached to Z lines
dark bands (A bands)
made up of thick filaments of myosin
Overlap actin
striation pattern of skeletal muscle fibers
I bands
A bands
H zone ( central region)
M line
Z line
Inside the sarcoplasm of a muscle fiber
network of channels surrounds each myofibril
sarcoplasmic reticulum
Formed by fibrous network of channels surrounding myofibrils
Transverse tubules (T tubules)
Membranous channels extending inward and passing through fiber
cisternae
Enlarged structures in which t tubules lie in between
Neurons (nerve cells)
conduct nerve impulses
Motor neurons
control effectors, which include skeletal muscle
Each skeletal muscle fiber is connected in a functional manner to
the axon of a motor neuro
synapse
functional connection
neurotransmitters
chemicals that enable communication
At the synapses
neurons communicate with other cells by releasing neurotransmitters
neuromuscular junction
the connection between a motor neuron and a muscle fiber
motor end plate
formed by specialized muscle fiber membrane
Motor end plates have
abundant mitochondria and nuclei, with greatly folded sarcolemmas
Most muscle fibers have
a single motor end plate
motor neuron axons have many branches connecting
the motor neuron to various muscle fibers
All muscle fibers contract when
When an impulse is transmitted
motor unit
is therefore made up of a motor neuron and the muscle fibers that it controls
Motor unit
Composed of a motor neuron and all of the muscle fibers it innervates
Skeletal muscles contract when
organelles and molecules that bind myosin to actin cause a pulling action
Myosin molecules are made up
two protein strands with globe-shaped cross-bridges that project outward
Actin molecules are globe-shaped with
binding “site” that attaches to myosin cross-bridges
Groups of many actin molecules
twist in double strands (helixes) to form an actin (thin) filament
troponin and tropomyosin
Included in the actin filament
One subunit of the troponin molecule
binds to tropomyosin,
troponin-tropomyosin complex
Bindings of one subunit of troponin and tropomyosin
subunit bonded to G actin
Hold the complex position
Muscle contractions cannot occur unless
position of the troponin-tropomyosin complex changes to expose the active sites on F actin
The functional unit of skeletal unit
Sarcomere
Sarcomers shorten
A skeletal muscle contracts
Cross bridges pulling on actin
sliding filament model
the way that sarcomeres shorten, with thick and thin filaments sliding past each other toward the center of the sarcomere, from both ends
Myosin filaments contain
ATPase in their globe-shaped portions
Atpase
Catalyzes the breakdown of ATP, add, and phosphate
Creating nrg
Myosin cross bridges position:
Cocked (binding to actin to pull filaments)
acetylcholine
neurotransmitter that stimulates skeletal muscle to contract
Acetylcholine releases into synaptic clef
rapidly diffuses, increasing certain protein receptors’ permeability to sodium
high calcium ion concentration
the sarcoplasmic reticulum responds by making the cisternae membranes more permeable, diffusing calcium into the sarcoplasm
Troponin and tropomyosin interact to form
linkages between actin and myosin filaments
Muscle relaxation
Caused by decomp of acetylcholine by acetyl cholinesterase
when fibers are active
ATP must be regenerated using existing ATP molecules in cell
ADP and phosphate
Regenerate ATP
Creatine phosphate
Regenerates ATP regeneration with high energy phosphate bonds
ATP breaks down
energy from creatine phosphate is transferred to ADP molecules to covert them back into ATP
Oxygen is required for
the breakdown of glucose in the mitochondria
Red blood cells
carry oxygen, bound to hemoglobin molecules
hemoglobin
the pigment that makes blood appear red in color
myoglobin
A pig Manet synthesized in the muscles to give reddish brown color
skeletal muscles are used for a minute or more,
anaerobic respiration is required for energy
anaerobic respiration
glucose is broken down via glycolysis to yield pyruvic acid, which reacts to produce lactic acid
Lactic acid can accumulate in muscles
diffuses in the bloodstream, reaching the liver, where it is synthesized into glucose
When exercising strenuously, oxygen is used
mostly to synthesize ATP
oxygen debt
Created as lactic acid increases
Low to moderate exercise
blood flow to provides enough oxygen for the cells’ needs
Glycolysis leads to formation
of pyruvic acid and aerobic respiration
For skeletal muscle
36 ATP per glucose is
Exhalation of carbon dioxide
oxygen supply to be lower than that which is needed by cells
Higher level exercise
Glycolysis leads to formation of lactic acid
In high levels of exercise
Results of high exercise
2 ATP per glucose is produced
The result is an accumulation of lactic acid
fatigue
Prolonged exercise may cause a muscle to become unable to contract
The cause of muscular fatigue
Lactic acid accumulation
Most of the energy that is released in cellular respiration becomes :
Heat
Muscle tissue generates a lot of heat because
Muscles formally of body mass
Body temperature is partially maintained by
the blood transporting heat generated by the muscle to other body tissues
myogram
Can be used to see contraction (twitch) of muscle
A muscle fiber will remain unresponsive until
the threshold stimulus is applied
The contractile response of a fiber to an impulse which consists of a period of contraction followed by a period of relaxation
twitch
When a muscle appears to be at rest, its fibers still undergo some sustained contraction
muscle tone or tonus
One end of a skeletal muscle usually is fastened to a relatively immovable part
origin
connects to a movable part
insertion
biceps brachii muscle of the arm
More than one origin or insertion
Skeletal muscles usually function in
groups
A muscle that contracts to provide most of a desired movement is called
prime mover or agonist
muscles work with a prime mover to make its action more effective
synergists
cause movement in the opposite direction
antagonists
elongated shapes with tapered ends
does not have the striations that skeletal muscle has because
Smooth muscle cells
has separated muscle fibers, and is found in the irises of the eyes as well as the walls of blood vessels
Multiunit smooth muscle
Visceral smooth muscle
is made up of sheets of cells that are spindle-shaped – it is found in the walls of hollow organ
a pattern of repeated contractions
which is caused by self-exciting fibers
rhythmicity
wavelike motion of many tubular organs
caused by these features of visceral smooth muscle
peristalsis
found only in the heart
up of striated cells that are connected into three-dimensional networks
Less calcium is stored
longer muscle twitches than in skeletal muscle
Cardiac muscle
Effects of Aging on
the Muscular System
tissues decrease in strength and size as we age
Skeletal muscle fibers become smaller in diameter as the number of myofibrils decreases
Skeletal muscles also become less elastic as fibrosis occurs
