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Comparative Anatomy Lecture Exam 3
Muscle System, Sense Organs, Nervous System, and Endocrine System
59
Anatomy
Undergraduate 4
11/07/2012

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Cards

Term

 

 

 

Major Effectors of Vertebrates Responsible for:

Definition
  • Body movement
  • Movement of most materials through the body
  • Support
  • Generation of heat
Term

 

 

 

Muscle cells are made of

Definition

 

 

 

Myofibrils

Term

 

 

 

Myofibrils are made of 

Definition

 

 

 

Myofilaments

Term

 

 

 

Types of Contraction

Definition
  • Isotonic
  • Isometric
  • Negative work
Term

 

 

 

Isotonic Contraction

Definition

 

 

Shortening of a muscle against a constant load or force

Term

 

 

 

Isometric Contraction

Definition

 

 

Little or no contraction although muscle is acting against a force

Term

 

 

 

Negative Work

Definition

 

 

Muscle fibers elongate rather than contract as tension increases

Term

 

 

 

Types of Muscle

Definition
  • Smooth muscle
  • Cardiac
  • Skeletal
Term

 

 

 

Smooth Muscle

Definition
  • Enlongated, nonstriated, spindle shaped cells
  • Provide slow, sustained contraction
  • Two Types:
    • Unitary smooth muscle
    • Multiunit smooth muscle
Term

 

 

 

Unitary Smooth Muscle

Definition
  • Occurs in most viscera
  • Myogenic (originating in muscle) contraction but modulated by nerve impulses
Term

 

 

 

Multiunit Smooth Muscle

Definition
  • Blood vessels
  • Eye
  • Neurogenic contraction
Term

 

 

 

Cardiac Muscle

Definition
  • Moderately elongated
  • Striated and branching cells tightly united by intercalating discs
  • Myogenic modulated by nerve impulse
  • One or more nuclei per cell
Term

 

 

 

Skeletal Muscle

Definition

 

 

Extremely long striated and multinucleated cells

 

Supports body and effects movement of the organism

Term

 

 

 

Motor Units

Definition

 

 

A neuron and the skeletal muscle fibers it innervates

Term

 

 

 

Motor End Plates

Definition

 

 

Points where branches of a neuron attach to muscle fiber

Term

 

 

 

Tonic Fibers

Definition
  • Contract slowly to provide tonus
  • Each muscle fiber reveives multiple motor endplates from the neuron innervating it
  • Extent and force of contraction are graded by frequency of nerve stimulation
  • Muscles that move the eyeball in mammals
  • A few postural muscles (affecting posture) in appendages of lower vertebrates

 

Term

 

 

 

Phasic Fibers

Definition
  • Most vertebrate skeletal muscle
  • Each muscle fiber receives a single muscle motor end plate
  • Contraction is "all or none"
  • Two types:
    • Slow phasic fibers
    • Fast phasic fibers
Term

 

 

 

Slow Phasic Fibers

Definition
  • Contract slowly
  • Adapted for slow, repetitive, isotonic contractions
  • Energy comes from oxidative metabolism
  • High myoglobin content
  • Example: dark meat on a chicken
Term

 

 

 

Fast Phasic Fibers

Definition
  • Contract rapidly
  • Adapted for rapid movements of short duration
  • Energy comes from anaerobic glycolysis
  • High glycogen content
  • Example: white meat on a chicken
Term

 

 

 

Strap and Fusiform Muscles

Definition
  • Muscle fibers long, run parallel to each other and to their tendon
  • Adapted for contractions resulting in extensive movement
  • Maximum strength of contraction
  • Examples: muscles of thigh region, sartorius, etc.
Term

 

 

 

Pennate Muscles

Definition
  • Short fibers that pull obliquely on their tendon
  • Cannot cause as extensive a movement but generate move force
  • Often found where space is limited
  • Well adapted for forceful isotonic contractions and isometric contractions of short extent
  • Examples: deltoid
Term

 

 

 

Muscle Grouping

Definition


The pattern of embryonic development of muscles and thier nerve supply provides the basis for divding muscles into groups whose homologies can be recognized in different vertebrate groups.

Term

 

 

 

Muscle Grouping using Embryology

Definition

 

 

Embryology is more meaningful in tracing evolution of the muscle system than is grouping based on histological or physical properties.

Term

 

 

 

Somatic vs. Visceral Muscles

Definition

 

  • Somatic muscles orient body with respect to the external environment
  • Visceral muscles are involved in maintaining an internal environment
Term

 

 

 

Somatic Muscles

Definition
  • Typically develop from myotomes
  • Axial
    • Muscles of body wall and tail - epaxials, hypaxials, and epibranchials
    • Hypobranchials and muscles of tongue
    • Extrinsic eyeball
  • Appendicular - muscles of the appendages
Term

 

 

 

Visceral Muscles

Definition
  • Typically develop from splanchnic mesoderm
  • Branchiomeric muscles - on visceral arches, muscles of tubes, vessels, and hollow organs
  • Also intrinsic eyeball (iris), heart, and erectors of feathers and hair
Term

 

 

Muscle of Fishes

Somatic Axial

Trunk Muscles

Definition
  • Form a series of muscles segments (myomeres)
  • Typically composed of slow phasic (for cruising and maintaining position against a current) and fast phasic (sudden bursts of speed) fibers
  • General structure of trunk musculature is closely correlated with swimming activity
Term

 

 

Muscles of Fishes

Somatic Axial

Epaxials and Hypaxials

Definition

  • Trunk muscles posterior to the gill region
  • Epaxials above and hypaxials below horizontal septum
Term

 

 

Muscles of Fishes

Somatic Axial

Epibranchials

Definition

 

  • Lie dorsal to the gill region
  • Forward continuation of epaxials and functions with them
Term

 

 

Muscles of Fishes

Somatic Axial

Hypobranchials

Definition
  • Somatic muscles ventral to gill region
  • Functionally associated with the visceral skeleton
  • Act to:
    • Open mouth
    • Expand pharynx during the intake of respiratory water current
Term

 

 

Muscles of Fishes

Somatic Axial

Extrinsic Ocular Muscles

Definition

  • 6 strap-shaped muscles attached to the outside of the eyeball
  • Responsible for movement of the eye
Term

 

 

 

Muscles of Fishes

Somatic Appendicular

Definition
  • Muscles of paired appendages, usually quite simple
  • Two types:
    • Dorsal abductor
    • Ventral adductor
Term

 

 

Muscles of Fishes

Somatic Appendicular

Dorsal Abductor

Definition

 

  • Runs between posterior dorsal portion of girdle and dorsal surface of fin
  • Pulls fin dorsally and caudally
Term

 

 

Muscles of Fishes

Somatic Appendicular

Ventral Adductor

Definition

 

  • Runs between anteroventral portion of girdle and ventral surface of fin
  • Pulls fin ventrally and crainally
Term

 

 

 

Muscles of Fishes

Visceral Branchiomeric

Definition
  • A very complex group assoicated with the elaborate visceral skeleton
  • They can be fairly variable according to specialization for feeding and respiration
Term

 

 

 

Evolutionary Trends in Muscles

Extrinsic Ocular Muscles

Definition
  • All tetrapods retain 6 muscles
  • Very little change in the process of terrestrialization
  • Only real change is in the rectus complex, which moves the upper and lower eyelids of birds and mammals
Term

 

 

 

Evolutionary Trends in Muscles

Hypobranchial Muscles

Definition
  • Become much more differentiated, associated with the complex hyoid apparatus and development of a muscular tongue
  • Involved in feeding and swallowing movements
  • Increase in nubmer of muscles in this group
Term

 

 

 

Evolutionary Trends in Muscles

Epibranchial and Epaxial Trunk Muscles

Definition
  • Very important in mediating dorsoventral bending of the spine
  • Control movements of the head
  • Segmentation lost or reduced in all tetrapods except salamanders
Term

 

 

 

Evolutionary Trends in Muscles

Hypaxial Muscles

Definition
  • Subdivided into 3 major groups:
    • Subvertebral group - lies just below vertebral column, interacts with epaxials
    • Rectus abdominus - longitudinally on either side of midventral line, supports abdomen
    • Lateral group - lie along flank, strengthen abdominal wall
Term

 

 

 

Evolutionary Trends in Muscles

Appendicular Muscles

Definition
  • Become large and numerous as appendages and girdles assume a major role in support and locomotion.
  • Early splay-legged tetrapods had large, powerful ventral muscles that adducted the humerous and femur and flexed the antebranchium and crus, raising the body from the ground
  • As limbs moved under the body the ventral musculature became less important for support
Term

 

 

Evolutionary Trends in Muscles

Branchiomeric Muscles

Mandibular Muscles

Definition
  • Closely follow changes in visceral skeleton
  • Most mandibular muscles still act on the jaw
    • Most close
    • One (digastric) opens
    • Tensor tympani follow part of the original mandibular arch into the middle ear, attached to the malleus (earbone) in mammals
    • Masseter, pterygoids, temporalis - closely related to evolution of the temporal fenestrae
Term

 

 

Evolutionary Trends in Muscles

Branchiomeric Muscles

Hyoid Muscles

Definition
  • Divided into 3 main components:
    • Part contribute to digastric
    • Part contribute to middle ear (stapedius)
    • Rest form superficial facial muscles
Term

 

 

 

Electric Organs

Definition
  • Modified muscle tissue in about 250 species of fish
  • Composed of a series of disk-shaped electroplaxes
  • May generate weak to strong pulses
  • Functions:
    • Weak - navigation, species recognition
    • Strong - stun predators as protective measure, or stun prey
Term

 

 

 

Electroplaxes

Definition
  • Modified muscle cells or their motor endplates
  • Multinucleated
  • Flat on the innervated side and highly folded on the opposite side
  • Myo fibrils are lost
Term

 

 

 

Purpose of Sense Organs

Definition

 



Vertebrates must be able to avoid predators, find shelter, food and mates, therefore they must by able to detect changes within their external and internal environments.

Term

 

 

 

Receptors

Definition

 

 

Transducers of mechanical, electrical, thermal, chemical, and radiant energy.

Term

 

 

 

General Receptors

Definition

 




Widely distributed in the body

Term

 

 

 

Special Receptors

Definition

 




Usually restricted to head region, usually paired

Term

 

 

 

Somatic Receptors

Definition

Two Types:

  • External receptors
  • Proprioceptors
Term

 

 

 

External Receptors

Definition

 



Somatic Receptor


Provide information about the external environment

Term

 

 

 

Proprioceptors

Definition

 



Somatic Receptor


Provide information about skeletal muscle activity

Term

 

 

 

Visceral Receptors

Definition

 



 

Monitor internal environment

Term

 

 

 

Neuromast Organs

Definition
  • Fishes and aquatic amphibians
  • Function primarily in mechanoreception and electroreception
  • May occur in shallow pits, grooves, ampullae, or canals, and forms the lateral line and cephalic canal system of fishes
  • Receptor cells are hair cells, which project into a gelationous secretion called the cupula
  • Bending the cupula causes changes in nerve impulses, which are detected
Term

 

 

 

Kinocilium

Definition

 




Special type of cilium on the apex of hair cells located in the sensory epithelium of the vertebrate inner ear.

Term

 

 

 

Cupula

Definition

 




A structure surrounding hair cell receptors

Term

 

 

 

Inner Ear

Definition
  • Sense organ present in all vertebrates
  • Neuromast System
  • Labyrinths are filled with endolymph
  • Perilymphatic space is filed with perilymph
  • Funtions in equilibration and audition
  • Lower vertebrates: 3 semicircular ducts, 2 membranous sacs, and the lagena (which becomes the cochlear duct in some reptiles, birds, and mammals
Term

 

 

 

Neuromast System

Definition

 




Membranous labyrinths located in skeletal labyrinth (otic capsule) surrounded by fluid-filled perilymphatic space

Term

 

 

 

Sensory Neuromast Sites

Definition

 



Located in squamous epithelium of the sacculus, utriculus, and lagena/cochlea (patches of hair cells found in these structures are called maculae), and an enlarged neuromast called a crista occurs in a swelling (ampulla) located at one end of each semicircular duct

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