Protection, Support &
Movement
GEC_MT109: Lecture Topic 6
__________
GLORINA DIVINA P. OROZCO, LPT, Ph.D.
CASE – Biology Dept
Learning Outcomes: Section 6.1
• Describe the integumentary system of
invertebrates.
• Explain the difference between hair and
nails.
Protection: Integumentary Systems
• The integumentary system is the external
covering of an animal.
• It primarily protects against mechanical
injury and invasion by microorganisms.
• Some diverse integumentary functions that
have evolved include:
– Regulation of body temperature
– Excretion of wastes
– Vitamin D formation
Protection: Integumentary Systems
(continued)
– Reception of environmental stimuli such as:
• Pain
• Temperature
• Pressure
– Locomotion
– Movement of nutrients and gases
The Integumentary System of
Invertebrates
• Single-celled protozoa have only a plasma
membrane for an external covering.
• Other protozoa have a thick covering called a
pellicle, outside the plasma membrane.
• Most invertebrates have n integument
consisting of a single layer of columnar epithelial
cells called an epidermis(figure 6.1).
• Specializations outside of this epithelial layer
may be in the form of cuticles, shells, or
teguments (figure 6.2a,b).
Figure 6.1 Integument of
Invertebrates.
The Integumentary System of
Vertebrates
• Skin is the vertebrate integument.
• Skin has two main layers:
– The epidermis
– The dermis
• A hypodermis consists of loose connective
tissue, adipose tissue, and nerve endings,
and separates the skin from the deeper
tissues.
Figure 6.2 Cuticles. (a) A crustacean
cuticle. (b) An insect cuticle.
Figure 6.2 Cuticles. (a) A crustacean cuticle.
(b) An insect cuticle
The Integumentary System of
Vertebrates (continued)
• The skin of jawless fishes
– Jawless fishes, such as lampreys and hagfishes, have
relatively thick skin (figure 6.3).
– The skin of cartilaginous fishes (e.g., sharks) is
multilayered and contains mucous and sensory cells
(figure 6.4).
– The skin of bony fishes (teleosts) contains scales
(figure 6.5).
– The skin of amphibians consists of a stratified
epidermis and a dermis containing mucous and
serous glands plus pigmentation cells (figure 6.6).
The Integumentary System of
Vertebrates (continued)
– The skin of nonavian reptiles reflects their
greater commitment to a terrestrial existence
(figure 6.7).
– The skin of avian reptiles shows many typically
reptilian features with no epidermal glands
(figure 6.8).
– The skin of mammals consists of several layers of
a variety of cells (figure 6.9).
Figure 6.3 Skin of
Jawless Fishes
Figure 6.4 Skin of
Cartilaginous Fishes.
Figure 6.5 Skin of
Bony Fishes.
Figure 6.9 Skin of Mammals.
The Integumentary System of
Vertebrates (continued)
– The notable features of mammalian skin are:
• Hair
• A greater variety of epidermal glands than in any other
vertebrate class
• A highly stratified, cornified, epidermis
• A dermis many times thicker than the epidermis
• Hair is composed of keratin-filled dead cells that
develop from the epidermis.
• Nails, like hair, are modifications of the
epidermis and are flat, horny plates on the
dorsal surface of the digits.
Learning Outcome: Section 6.2
• Compare hydrostatic skeletons, exoskeletons,
and endoskeletons.
The Skeletal System of Invertebrates
• Animals have three types of skeletons:
– Hydrostatic skeletons
– Exoskeletons
– Endoskeletons
• These skeletons function in animal
movement that requires muscles working in
opposition (antagonism) to each other.
The Skeletal System of Invertebrates
(continued)
• The hydrostatic skeleton is a core of liquid
(water or a body fluid such as blood) surrounded
by a tension-resistant sheath of longitudinal
and/or circular muscle (figures 6.10a-c).
• Hydrostatic skeletons are found in invertebrates
and can take many forms and shapes:
–
–
–
–
–
The gastrovascular cavity of acoelomates
The rhynchocoel in nemerteans
A pseudocoelom in aschelminths
A coelom in annelids
A hemocoel in molluscs
Figure 6.10a Hydrostatic Skeletons.
(a) Sea anemones.
Figure 6.10b
How a
hydrostatic
skeleton
changes to
shorten or
open.
Figure 6.10bc
The Skeletal System of Invertebrates
(continued)
• Rigid exoskeletons have locomotor functions
because they provide sites for muscle
attachment and counter-forces for muscle
movements.
• Exoskeletons also support and protect the body,
but these are secondary functions.
• Certain regions of the arthropod body have a
thin’ flexible cuticle and joints (figure 5.11).
• The exoskeleton of invertebrates also contains
calcium carbonate crystals that make it hard and
inflexible, except at the joints.
Figure 6.11 Exoskeletons.
(a) A cicada nymph.
Figure 6.11b
Articulation of
an arthropod
limb.
The Skeletal System of Vertebrates
• The most familiar endoskeletons, both
cartilaginous and bony, first appeared in the
vertebrates.
• This endoskeleton consists of two main types
of supportive tissue:
– Cartilage
• Provides a site for muscle attachment
• Aid in movement at joints
• Provides support
The Skeletal System of Vertebrates
(continued)
– Bone (figure 6.12)
• Provides a point of attachment for muscles
• Transmits the force of muscle contraction from one
part of the body to another
– The skeleton of fishes
– Most jawed fishes have an axial skeleton.
(figure 6.13)
– The skeleton of tetrapods evolved to be
supportive on land (figure 6.14).
The Skeletal System of Vertebrates
(continued)
• The human skeleton has two major parts:
– The axial skeleton
•
•
•
•
Skull
Vertebral column
Sternum
ribs
– The appendicular skeleton
• Appendages
• Pectoral girdle
• Pelvic girdles
28
Human
Skeletal
System
© 2019 McGraw-Hill Education
Frog
Skeletal
System
Figure 6.13 Fish
Endoskeleton.
Figure 6.12
Bone.
Learning Outcomes: Section 6.3
• Describe three types of nonmuscular
movements.
• Explain the sliding-filament mechanisms of
muscle contraction.
Movement: Nonmuscular Movement
and Muscular Systems
• Movement (locomotion) is characteristic of
certain cells, protists, and animals.
• Nonmuscular movement involves the
following structures:
– Pseudopodia
– Cilia
– Flagella
• The contractile proteins actin and myosine
are involved.
Movement: Nonmuscular Movement
and Muscular Systems (continued)
• Amoeboid movement does not involve
muscles.
– Pseudopodia are involved (figure 6.15).
– Ciliary movement involves metachronal
(coordinated) waves passing along rows of cilia
(figure 6.16).
Figure 6.15 Mechanism of
Amoeboid Movement.
Figure 6.16 Ciliary
Movement.
Protists’ Movement
https://youtu.be/Ln69k7LyTsU
An Introduction to Animal Muscles
• Animals may have one or more of the
following types of muscle tissue:
– Smooth muscle
– Skeletal muscle
– Cardiac muscle
• Muscle tissue exhibits contractility,
excitability, extensibility, and elasticity.
An Introduction to Animal Muscles
(continued)
• The muscular system of invertebrates
– Locomotion of soft-body invertebrates involves:
• Pedal locomotion in snails and planarians
• Successive muscle contraction in earthworms
(figure 6.17)
• Looping movements in leeches (figure 6.18)
• Water-vascular system of echinoderms (figure 6.20)
• Terrestrial locomotion in invertebrates also involves
walking (figure 6.22).
• Flight
• Jumping (6.23)
Figure 5.17 Successive Stages in
Earthworm Movement.
Figure 6.18 Looping
Movements.
Figure 6.19 WaterVascular System of an
Echinoderm.
Figure 6.20
Jump of a Flea.
The Muscular System of Vertebrates
• Most of the musculature of fishes consists of
segmental myomeres (figure 6.24).
• Skeletal muscle structure is illustrated in figure 6.25.
• The sliding-filament model of muscle contraction is
shown in figure 6.26.
– This involves sliding of myofilaments within myofibrils.
• The nerve-muscle motor unit is shown in figure 6.27.
– Nerves control skeletal muscle contraction.
– The process of contraction is controlled by calcium ions
(figure 6.28).
Figure 6.24a Fish
Musculature.
Figure 6.25
Structure of
Skeletal Muscle
Tissue.
Figure 6.26
Sliding-Filament
Model of
Muscle
Contraction
Figure 6.27 Nerve-Muscle Motor Unit,
https://drive.google.com/file/d/17bQCQjQP9CAiTOD4MoJ3AgF7cBpJ6IJ4/vie
w?usp=sharing
Overview of Muscle Anatomy & Contraction
Figure 6.28 Model of Calcium-Induced Changes in Troponin
That Allow Cross-Bridges to Form Between Actin and Myosin.
https://drive.google.com/file/d/1ZeErnMbOTSBUl_q5sXChdHpSSbsYJ
WEr/view?usp=sharing
Action Potential & Actin-Myosin Binding
Thank you for listening!!
Be ready for a QUIZ next meeting