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BSC 105Muscles

Ability for muscles to contract Contractility
4 major characteristics of muscle contraction? Contractility, excitability, extensibility, and elasticity
What is the most superficial layer of a muscle? Fascia
What is the capacity of skeletal muscle to respond to a stimulus? Excitability
What is the ability to be stretched? Extensibility
What is the ability to recoil to their original length after stretching? Elasticity
Connective tissue sheath around the skeletal muscle? Epimysium
Muscle cells Muscle fibers
What shape is each muscle fiber? Cylindrical
What does each muscle fiber contain? Several nuclei
What are the numerous bundles that make up muscles called? Fasciculi
What surrounds each individual muscle fiber? Endomysium
What are myofibrils? Threadlike structures that fills the cytoplasm
What are the 2 major protein fibers? Actin Myofilaments and Myosin myofilaments
Which myofilament is thinner? Actin or myosin? Actin
Which myofilament is thicker? Actin or myosin? Myosin
What does actin resemble? 2 minute strands of pearls twisted together
What does myosin resemble? Bundles of minute golf clubs
What does actin and myosin form? Sarcomeres
What is the basic structural and functional unit of the muscle? Sarcomeres
What defines a sarcomere? Z line to Z line
What does the I band consist of? Actin
What is the loose connective tissue sheath that surrounds the fasciculi called? Perimysium
How does the arrangement of actin and myosin affect the appearance of sacromeres? Banded appearance
What is found on each side of the Z line? I band
What is the A band? The darker central region in the central region of each sacromere
What does the A band consist of? Myosin
What is the light zone in the center of each sarcomere? H zone
What does the H zone consist of? Only Myosin
What is the dark staining line in the center of the sarcomere? M line
Where are the myosin myofilaments anchored at? M line
How is the outside of the cell membrane charged compared to the inside? Positively
How is the inside of the cell membrane charged? Negatively
What is the charge difference across the membrane called? Resting membrane potential
What happens to a muscle cell when it is stimulated? Characteristics change briefly
What is the brief reversal back of the charge called? Action potential
What are nerve cells that carry action potentials to skeletal muscle fibers? Motor neurons
What enters the muscles and branch? Axons
What does each axon branch that connects to the muscle form? Neuromuscular junction (synapse)
Where does a neuromuscular junction (synapse) form? Center of the cell
What is a single motor neuron and all the skeletal muscle fibers it innervates called? Motor unit
How is a neuromuscular junction formed? Enlarged nerve terminal resting in an indentation of the muscle cell membrane
What is the enlarged nerve terminal called? Presynaptic terminal
What is the space between the presynaptic terminal and the muscle cell? Synaptic cleft
What does each presynaptic terminal contain? Synaptic vesicles
What do synaptic vesicles secrete? Acetylcholine
What does acetylcholine diffuse across? Synaptic cleft
What does acetylcholine do when it binds to the postsynaptic terminal? Causes change in postsynaptic cell
What happens when action potential reaches the nerve terminal? Synaptic vesicles release acetylcholine into the synaptic cleft by exocytosis
The acetylcholine diffuses across the synaptic cleft in order to do what? Bind to receptor molecules in the muscle cell membrane (sarcolemma)
What is another name for the muscle cell membrane? Sarcolemma
What does the combination of acetylcholine and its receptor cause? An increase of sodium ions
What does this influx initiate in the muscle cell? Action potential, causing it to contract
What happens to the acetylcholine when it is released back into the synaptic cleft between the neuron and muscle cell? Rapidly broken down by enzymes
What enzyme breaks down acetylcholine? Acetylcholinesterase
What does the enzymatic breakdown ensure? One action potential in the neuron yields only one action potential in the skeletal muscle, and only one contraction of skeletal muscle
When does muscle contraction occur? As actin and myosin are sliding past each other causing the sarcomeres to shorten
What happens when the sarcomeres shorten? The muscle shortens
What is the sliding of actin myofilaments past myosin myofilaments during contraction called? Sliding filament mechanism
Which bands in the sarcomeres get shorter when the muscles contract? H and I bands only
True/False: The A band shorten during muscle contraction. False
What is a muscle twitch? Contraction of of an entire muscle in response to a stimulus that causes action potential in one or more muscle fibers
What is a muscle fiber that will not respond to a stimulus until that stimulus reaches a threshold that causes it to contract maximally called? All-or-nothing response
What is the time between application of a stimulus to a motor neuron and the beginning of a contraction called? Lag phase
What is the time of contraction called? Contraction phase
What is the time during which the muscle relaxes called? Relaxation phase
What is the condition where the muscles remain contracted without relaxing called? Tetany
What is the increase in number of motor neurons being activated called? Recruitment
If successive stimuli are given, what will happen to the muscle? It will contract so frequently it won't have time to relax, which could lead to tetany
What is ATP? Adenosine triphosphate
What is needed for energy for muscle contractions? ATP
Where is ATP produced? Mitochondria
How long does ATP last? Is it stable? ATP is short-lived and unstable
What does ATP degenerate to in order to become more stable? ADP plus a phosphate
What does ADP stand for? Adenosine diphosphate
What do muscle cells have to constantly produce? ATP
Can ATP be stockpiled or stored when at rest? No
What high-energy molecule can be stored? Creatine phosphate
What is energy molecules in ATP used to synthesize during periods of inactivity? Creatine phosphate
What can be accessed quickly during periods of activity and be used to produce ATP to be used in muscle contraction? Creatine phosphate
What is anaerobic respiration? Without oxygen
What is aerobic respiration? With oxygen
Which is more efficient? Anaerobic or aerobic respiration? Aerobic
Why does breathing rate stay elevated for a short time after exercising even though the muscles are not actively contracting? Pay back the oxygen debt
What is the oxygen debt? Amount of oxygen needed to convert lactic acid to glucose and replenishes depleted creatine phosphate stores
How does muscle fatigue occur? ATP is used during muscle contraction faster than it can be produced
What are the 2 types of muscle contractions? Isotonic and isometric
What is isotonic muscle contractions? Equal tension-Tension produced is constant, but the length changes
What is isometric contractions? Equal distance- The length of the muscle does not change, but the tension changes
What does "Muscle tone" refer to? Constant tension produced by muscles for long periods of time; keeps head up and back straight
What are fast=twitch fibers? Muscles that contract and fatigue quickly; adapted to anaerobic processes
What is an example of a fast-twitch muscle? White meat of a chicken breast
What are slow-twitch fibers? Contract more slowly and more resistant to fatigue; better suited to aerobic processes
What is an example of a slow-twitch fiber? Dark meat of a duck breast or the legs of a chicken
What are the points of attachment for muscles? Origin and Insertion points
What connects that muscle to the body at these points? Tendons
What is the origin of a muscle? The most stationary part (head) of a muscle
What is the insertion point of a muscle? End undergoing the greatest movement
What is the portion of the muscle between the origin and insertion called? Belly
Can muscles have more than one head or origin? Yes, some muscles have multiple heads or origins
What are muscles that work together to accomplish specific movements called? Synergists
What are muscles that work in opposition to one another called? Antagonists
If one muscle plays a major role in accomplishing the desired movement among synergists, what is it called? Prime mover
How are muscles named? Descriptively; some include location, size, orientation of fibers, shape, origin, insertion, and function
What muscle raises the eyebrows? Occipitofrontalis
What muscle closes the eyelids and cause "crows feet" wrinkles in the skin at the corners of the eye> Orbicularis oculi
What muscle puckers the lips? Orbicularis oris
What flatten's the cheeks and is also called the trumpeters muscle? Buccinator
What is the smiling muscle? Zygomaticus
What is the sneering muscle? Levator labii superioris
What is the frowning muscle? Depressor anguli oris
What is another name for chewing? Mastication
How many pairs of mastication muscles do we have? 4
What are the 4 pairs of mastication muscles? 2 pairs of pterygoids, temporalis, and masseter
What does the intrinsic tongue muscles do? Change the shape of the tongue
What does the extrinsic tongue muscles do? Move the tongue
What is the lateral neck muscle and prime mover? Sternocleidomastoid
What movement does it allow? Rotates and abducts the head
What is the group of muscles on each side of the back? Erector spinae
What are the erector spinae responsible for? Keeping the back straight and the body erect
What are the muscles that move the thorax? Thoracic muscles
Which two muscles are the most involved in breathing? External intercostals and internal intercostals
What do the external intercostals do? Elevate the ribs during inspiration
What do the internal intercostals do? Contract during forced expiration
What does the diaphragm do? Accomplishes quiet breathing; aids in breathing
What shape is the diaphragm? Dome-shaped
What are the hamstring muscles? Posterior thigh muscles
What does the hamstring do? Flexes the leg and extends the thigh
What two muscles form the calf muscle? Gastrocnemius and soleus
What tendon does the joined gastrocnemius and soleus form? Achiles
What does the achilles do? Flexes the foot and toes
What are the lateral muscles of the leg called? Peroneus muscles
What are peroneus muscles primarily responsible for? Turning the foot outward
What is one other thing that the peroneus muscles aid in? Plantar flexion
How many muscles are located in the foot? 20
What are the foot muscles called? Intrinsic foot muscles
What do the intrinsic foot muscles do? Flex, extend, abduct, and adduct the toes
What does the trapezius muscles do? Rotate the scapula
What does the Serratus anterior muscle do? Pulls scapula anteriorly
What muscles attaches the arms to the body? Pectoralis major and latissimus dorsi muscles
What movements does the pectoralis major allow? Adducts and flexes the arm
What movements does the latissimus dorsi allow? Medially roatates, adducts, and powerfully extends the arm
What is another name for the latissimus dorsi? Swimmer muscles
What attaches the humerus to the scapula and clavicle? Deltoid
What is the major abductor of the upper limb? Deltoid
What does the triceps brachii muscle do? Extends the forearm
Where is the triceps brachii located? Posterior compartment of the arm
What does the biceps brachii do? Flexes the forearm
Where is the biceps brachii located? Anterior compartment of the arm
What does brachialis do? Flexes forearm
What does the brachiordialis do? Flexes and supinates the forearm
What does the flexor carpi do? Flexes the wrist
What does the extensor carpi do? Extends the wrist
What does the flexor digitorium do? Flexes the fingers
What does the extensor digitorium do? Extends the fingers
What are the hand muscles called? Intrinsic hand muscles
What muscle is responsible for the abduction and adduction of the fingers? Interossi muscles
How many intrinsic hand muscles do we have? 19
Where are the interossi muscles located? Between the metacarpals
What is the strong band of fibrous connective tissue that covers the flexor and extensor tendons and holds them in place around the wrist so they don't bowstring during muscle contraction? Retinaculum (bracelet)
What is the gluteus maximus? Buttocks
What is the gluteus medius? Hip muscle and common injection site
What contributes most of the mass to the buttocks? Gluteus maximus
What muscle extends the leg? Quadriceps femoris
Where is the quadriceps femoris? Anterior thigh muscles
What is the sartorius? Tailors muscle
What does the sartorius do? Flexes the thigh
What motions is the muscles of the anterior abdominal wall responsible for? Flexes and rotates the vertebral column, compresses the abdominal cavity, and holds in the abdominal viscera
What is visible in the person visible in a person with relatively little fat? Vertical linear indentation
How far does the vertical linear indentation stretch? From the sternum, through the navel, to the pubis
What is the tendinous area of the abdominal wall that the vertical linear indentation strecth through called? Linea alba
What does the linea alba consist of instead of muscle? White connective tissue
What is found on each side of the linea alba? Rectus abdominus
What crosses the rectus abdominus at three or more locations, making a muscled person appear segmented (abs)? Tendinous inscriptions
What is lateral to the rectus abdominus? Layers of muscle
What are the muscles lateral to the rectus abdominus from superficial to deep? External abdominal oblique, internal abdominal oblique, and transverse abdominis muscle
How are the fasciculi of the 3 muscle layers oriented? In opposite directions of each
What happens when these muscles contract? They compress the abdominal contents
About how many taste buds do adults have? About 4,000
What are the 5 major taste receptors? Sweet, salty, sour, bitter, and umami
About what percent of what we taste is actually due to our sense of smell? 80%-90%
What does our sense of smell depend on? 10 to 20 million olfactory cells
Where are our olfactory cells located at? Olfactory epithelia high in the roof of the nasal cavity
What are olfactory cells? Modified neurons
What are the 3 layers of the eye? Sclera, choroid, and retina
What is the superficial (outer) layer of the eye? Sclera
What is the white of our eyes? Sclera
What is the cornea made up of? Transparent collagen fibers
What is the cornea also known as? The window of our eye
What is the only organ that can be transplanted without taking rejection medicine? Cornea
What is the thin, middle coat of the eye? Choroid
What does the choroid have? Extensive blood supply
What does the dark pigments of the choroid absorb? Stray light rays
What is found in the choroid layer and regulates the size of the pupil? Iris
What is the colored portion of the eye? Iris
What is found behind the iris? Ciliary body containing ciliary muscle
What does ciliary body control? Shape of the lens
What attaches the lens to the ciliary body? Suspensory ligaments
What does the lens attachment do for the eye? Divides it into two compartments
What is the anterior compartment of the eye filled with? Aqueous fluid
How much aqueous fluid is made daily? How does it leave? A small amount and leaves through tiny ducts
What occurs when the tiny aqueous ducts become blocked? Glaucoma
What can glaucoma lead to? Total blindness
What is the third and deep layer of the eye? Retina
Which compartment is the retina located in? Posterior compartment
What fills the posterior compartment? Clear, gelatinous fluid called vitreous humor
What does the vitreous humor do? Holds the retina in place and supports the lens
What are the two photoreceptors in the retina called? Rods and cones
What controls our peripheral vision? Can they detect color? Rods; no they don't collect color
What controls our center vision? Can they detect color? Cones; Yes they collect color
What do sensory fibers from the retina form? Optic nerve
What part of the eye collects nerve signals from the brain? Optic nerve
How is the blind spot described? No rods or cones at the optic nerve
Is vision possible in the blind spot? No, it's the blind spot for a reason
What are 4 abnormalities of the eye Colorblindness, nearsightedness, farsightedness, and astigmatism
What is colorblindness? You cannot see certain colors
What is the most common colorblindness? red-green colorblindness
Are males or females more susceptible to colorblindness? Males, it is on the X chromosome
What is nearsightedness? You can see up close, but not far away
What is farsightedness? Can see far away, but not up close
What is astigmatism? Light is not evenly focused on the retina
What are some causes for astigmatism? The cornea or lens is uneven, making the image fuzzy
What are the 3 divisions of the ear? Outer, middle, and inner
What does the outer division of the ear consist of? Pinna (external flap) and auditory canal
What lines the auditory canal? Fine hairs and sweat glands
What is located in the upper wall of the auditory canal? Modified sweat glands
What do modified sweat glands secrete? Earwax
What does earwax do? Substance that guards the ear against the entrance of foreign materials; air pollutants
Where does the middle division of the ear begin and end? Begins-Tympanic membrane (eardrum) Ends-oval and round windows
What is the bony wall containing two small opening covered by membranes in the ear? Oval and Round windows
What are the three small bones found between the tympanic membrane and oval window called? Ossicles
What are the names of the 3 bones found between the tympanic membrane and oval window? Malleus (hammer), incus (anvil), and stapes (stirrups)
What does the names of the 3 bones reveal? Their actual shapes
Where does the auditory (Eustachian tubes) extend to? Middle ear to nasopharynx
What does the Eustachian tubes do? Equalize air pressure
What fills the middle and outer air? Air
What fills the inner ear? Fluid
What are the 3 areas of the inner ear? Semicircular canals, vestibule, and cochlea
What does the semicircular canals and vestibule deal with? Equilibrium
What does the cochlea deal with? Hearing
What shape does the cochlea resemble? Snail's shell
What does the CNS (Central Nervous System) consist of? Brain and spinal cord
What does the PNS (Peripheral Nervous System) consist of? Nerves and their receptors, synapsis, and ganglia that lie outside the CNS
What does the afferent division transmit? Action potentials from sensory organs to the CNS
What does the efferent division transmit? Action potentials from the CNS to the effector organs, such as muscles and glands
What does the somatomotor nervous system transmit? Impulses from CNS to skeletal muscle
What does the autonomic nervous system transmit? Transmits action potentials from the CNS to smooth muscle, cardiac muscle, and glands
What are nerve cells? Neurons
What do neurons do? Receive stimuli and transmit action potentials to other neurons or to effector organs
What does a neuron consist of? Cell body and 2 types of processes: Dendrites and Axons
How many nuclei does each neuron cell body contain? One
What is the function of dendrites? Receive information from other neurons or sensory receptors and carry the information to the cell body
What are dendrites? Short, highly branching cytoplasmic extensions that are tapered from their cell body to their tips. Most are extensions of the cell body
What is the function of axons? Carry information away from the cell body
What surrounds most axons? Myelin sheath
What can axons do structurally? Remain single or branch to form a collateral axon
What is neuroglia? What is another name for it? Nerve glue; glial cells
Are neuroglia more numerous than neurons? Yes, they are more numerous
What forms the myelin sheath around the axons? Schwann cells
What is the gap between Schwann cells called? Nodes of Ranvier
Are axons either completely covered or partially covered by myelin sheaths? Both
What do groups of nerve cell bodies and their dendrites form? Gray matter
What is gray matter on the surface of the brain called? Cortex
What are gray matter clusWhat are ters deep within the brain called? Nuclei
What are bundles of axons and their connective tissue sheaths called in the PNS? Nerves
Where is the brain housed? Cranial vault
What are the 4 major regions of the brain? Brainstem, dencephalon, cerebellum, and cerebrum
What 3 structures make up the brainstem? Medulla Oblongata, pons, and midbrain
What does the brainstem do? Connects the spinal cord to the remainder of the brain and is responsible for many functions.
What does damage to the brainstem often result in? Death
What is the medulla oblongata? Most inferior part of the brain and is continuous with the spinal cord
What are some functions of the medulla oblongata? Regulate heart rate, blood vessel diameter, breathing, swallowing, vomiting, coughing, sneezing, balance, and coordination
What are the 2 prominent enlargements that extend the length of the medulla called? Pyramids
What are pons? Where is it located compared to the medulla oblongata? Bridge-superior to the medulla oblongata
What do pons do? Relay information
Where are pons located? (In general) Between the cerebrum and cerebellum
What does "bridge" describe for pons? Structure and function
Where is the midbrain located compared to the pons? Superior to the pons
What does the midbrain consist of? 4 mounds called colliculi
What are colliculi involved in? Hearing and visual reflexes
What is reticular formation? Scattered nuclei that play a role in the sleep/wake cycle
How do general anesthetics function? They suppress the reticular formation
What could damage to the reticular formation cause? Coma
What can the removal of visual or auditory stimuli lead to? Drowsiness
What is the dencephalon? Part of brain between the brainstem and cerebrum
What are the components of the dencephalon? Thalamus, pineal body, and hypothalamus
What is the largest portion of the dencephalon? Thalamus
What shape is the thalamus? Yo-yo shaped
What does the thalamus do? Registers an unconscious, unlocalized, uncomfortable perception of pain
Where is the pineal body located compared to the thalamus? Posteriorly
What type of gland is the pineal body? Endocrine gland
What shape is the pineal body? Pine-cone shaped
What can the pineal body influence? The onset of puberty
What is another major thing the pineal body may play a role in? Hibernation
What is the most inferior part of the diencephalon Hypothalamus
What is the hypothalamus important in maintaining? Homeostasis
What does the hypothalamus play a central role in? Control of body temp., hunger, thirst, good feelings, rage, fear, etc.
What is the funnel-shaped stalk that extends from the floor of the hypothalamus to the pituitary gland? Infundibulum
What do the mammilary bodies involve? Olfactory reflexes
What do mammilary bodies gather and control? Emotional responses to odors and memory
What si the largest portion of the brain? Cerebrum
What is the cerebrum divided into? Left and right hemispheres by a longitudinal fissure
What are the numerous fold that greatly increase the surface area of the cortex? Gyri
What is the intervening grooves of the cerebrum? Sulci
What is each hemisphere of the cerebrum divided into? Lobes
How are the lobes of the cerebrum named? For the bones that are over them
What are the 4 lobes of the cerebrum? Frontal lobe, Parietal lobe, occipital lobe, and temporal lobes
What is the frontal lobe important in? Voluntary motor function, motivation, agression, and mood
What is the parietal lobe the principal center for? Reception and evaluation of most sensory info such as touch, balance, and taste
What does the occipital lobe function in? Reception and integration of visual input and is not distinctly separate from other lobes
What does the temporal lobe evaluate? Olfactory and auditory input
What is the temporal lobe important in? Memory; abstract thought and judgement
What are the 3 types of memory? Sensory, short-term, and long-term
How long does sensory memory retain information? Less than a second
How long does short-term memory retain information? Few seconds to a few minutes
Can sensory memory become short or long-term memory? Yes, but only if it is valuable
What is sensory memory described as? Brief retention of sensory input as it is scanned, evaluated, and acted upon
How long does short-term memory last About 30 minutes
How many bits of information is short-term memory usually limited to? About 7 bits of information
What can happen to large amounts of information to become short-term memory? It can be chunked
What will happen if your temporal lobe is damaged? You will live in the present and remote-past (Think 50 First Dates)
What can long-term memory involve? Physical change in neuron shape
What bits of information does long-term memory usually store? Important information such as address, how to get home, and all important numbers in life
What does the right cerebral hemisphere control? Muscular activity and receives sensory input from the left half of the body
What does the left cerebral hemisphere do? Controls input from the right half of the cerebrum
What separates the cerebrum into halves? Longitudinal fissure
Created by: bmfortn1



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