8 Skeletal System (X) Flashcards
What are the main functions of the skeletal system? (5)
- Support
- protection
- movement
- mineral depot
- blood synthesis
What are the types of skeletons? (2)
- Hydrostatic skeleton
- rigid skeleton (exoskeleton, endoskeleton)
A type of skeleton that supports body form and provides resistance for muscle contraction.
hydrostatic skeleton
What is the source of a hydrostatic skeleton?
Some organisms use a:
- fluid-filled gastrovascular cavity
- fluid-filled coelom
How do earthworm muscles function without a firm base? How do earthworms move?
1) They contract against incompressible coelomic fluids in a limited space.
2) By alternate contractions of circular and longitudinal muscles, creating waves that propel them forward.
Structures like hydrostatic skeletons, composed of incompressible tissues with constant volume and complex muscle arrangements.
muscular hydrostats
A type of skeleton that consist of rigid elements, usually jointed, provide muscle attachment.
rigid skeletons
What are the two principal types of rigid skeletons? (2)
- Exoskeleton
- endoskeleton
A principal type of rigid skeletons that functions for protection and locomotion.
exoskeleton
The exoskeleton of molluscs and arthropods are composed of?
- molluscs - caclium carbonate
- arthropods - chitin
A principal type of rigid skeletons that function as support, protection, and reservoir for calcium and phosphorus. It grows with the animal, does not limit internal organ space, supports greater weight.
endoskeleton
Where are endoskeletons found? (2)
- echinoderms
- vertebrates.
What materials make up an endoskeleton?
mineralized bone and cartilage
A semi-rigid supportive axial rod in protochordates and all vertebrate larvae and embryos. Large, vacuolated cells surrounded by elastic and fibrous sheaths.
notochord
What is the function of the notochord?
Acts as a stiffening device.
What happens to the notochord in vertebrates during development?
surrounded or replaced by the backbone
- except in jawless vertebrates
A soft, pliable tissue that resists compression and serves as a major skeletal element in some vertebrates.
cartilage
Which vertebrates have a purely cartilaginous skeleton? (2)
- Jawless vertebrates
- elasmobranchs (like sharks)
Hyaline or fibrocartilage with calcium salts deposited within the interstitial substance.
calcified cartilage
Where is calcified cartilage found? (3)
- jaws of sharks
- radula of gastropods
- cephalopod mollusks.
A living tissue with significant deposits of calcium salts in the extracellular matrix.
bone
Types of Bones Based on Density (2)
- compact (osteon) bone
- spongy (cancellous) bone
Dense bone with layers of mineralized collagenous bundles arranged around a Haversian canal containing blood vessels, lymph vessels, and nerves.
compact (osteon) bone
An open, interlacing framework of bony tissue with marrow cavities lined by endosteum.
spongy (cancellous) bone
Rigid frameworks in spongy bone that provide maximum strength at stress points.
trabeculae
Connective tissue fibers that support blood vessels, nerve fibers, and adipose tissue (yellow marrow).
bone marrow
It contains hemopoietic tissue that produces red blood cells (RBCs) and some white blood cells (WBCs).
red marrow
A thin connective tissue lining the marrow cavity, involved in calcium deposition and bone remodeling.
endosteum
In early bone development, they act as models for future bones, where calcium salts are deposited to form the bone matrix.
cartilage structures
A process where cartilage is replaced by bone during development.
endochondral ossification
They break down bone, remove worn cells, and deposit calcium in the blood.
osteoclasts
What hormones increases and decreases osteoclast activity to release calcium?
- increase: Parathyroid hormone (PTH)
- decrease: Calcitonin
They work with osteoblasts to repair and renew bone tissue.
osteoclasts
They are bone-forming cells responsible for building new bone tissue.
osteoblasts
A hormone that inhibits bone resorption to help reduce calcium levels in the blood.
Calcitonin
A hormone that stimulates bone resorption to increase calcium levels in the blood. It helps maintain constant calcium levels in the blood.
Parathyroid hormone (PTH)
It helps maintain constant calcium levels in the blood, supporting bone mineralization.
1,25-dihydroxyvitamin D
The process of bone resorption and replacement, which accommodates brain growth or responds to mechanical stress.
skeletal remodeling
What are the two main divisions of the vertebrate skeleton? (2)
- axial skeleton
- appendicular skeleton
What does the axial skeleton include? (4)
- skull
- vertebral column
- sternum
- ribs
What does the appendicular skeleton include? (5)
- Limbs
- fins
- wings
- pectoral girdle
- pelvic girdle
The human skeleton supports and protects the body, permits movement, provides a foundation for muscles, stores __ and __ions, and produces __ in certain bones.
- calcium; phosphate
- red blood cells (RBCs)
Protects the brain and house sensory organs.
skull
Support the head and trunk, protect the spinal cord, and protect the roots of spinal nerves.
vertebral column
What are the segments of the vertebral column from superior to inferior? (5)
- 5 Cervical vertebrae (neck)
- 12Thoracic vertebrae (chest)
- 5 Lumbar vertebrae (small of back)
- Sacral (5 fused sacrum/pelvic)
- Coccyx (tailbone)
Protect the heart and lungs and assist with breathing.
rib cage
What provides support for the rib cage?
thoracic vertebrae
How many pairs of ribs are there in the human rib cage?
12 pairs
What are true ribs, and how many pairs are there?
Ribs that connect directly to the sternum, with seven pairs.
What are false ribs, and how many pairs are there?
Ribs that do not connect directly to the sternum, with five pairs.
Ribs that do not connect to any bony or cartilaginous structure ventrally.
floating ribs
What does the appendicular skeleton in human consist of? (3)
bones within
- pectoral girdles
- pelvic girdles
- attached limbs
What bones make up the pectoral girdle, and what does it support?
bones of the shoulder, supporting the arms and hands; located anteriorly.
What bones make up the pelvic girdle, and what does it support?
The bones of the pelvis, supporting the legs and feet; located posteriorly.
A site where two bones or cartilage meet.
arthrosis
What are the kinds of arthrosis?
- Diarthrosis (Synovial Joint)
- Amphiarthrosis (Cartilaginous Joint)
- Synarthrosis (Fibrous Joint)
A freely movable joint in one or more planes, with articular surfaces covered by hyaline cartilage and enclosed in a fibrous capsule lined by a synovial membrane that secretes lubricating fluid.
Diarthrosis (Synovial Joint)
Give an example of a diarthrosis joint.
Knee and elbow joints in mammals.
A joint where fibrocartilage unites the components, has a fibrous joint capsule, no synovial membrane, and permits limited movement. Ex. The joint between the centra of mammalian vertebrae.
Amphiarthrosis (Cartilaginous Joint)
An immovable joint where bones are joined by an irregular, jagged suture. Can be found in the roof of the skull (sutured joint)
Synarthrosis (Fibrous Joint)
irregular jagged seam at the junction of two bones that renders the joint immovable; roof of the skull
suture
