Skeletal system

Question 1

What are the three major types of skeletons found in the animal kingdom?

Answer 1

• Hydrostatic skeletons
• Exoskeletons
• Endoskeletons

Each type of skeleton serves different functions and adaptations in various animal groups.

Question 2

Define hydrostatic skeleton.

Answer 2

A fluid-filled body cavity enclosed by the body wall

In cnidarians, the gastrovascular cavity acts as the hydrostatic skeleton.

Question 3

What types of muscle layers are involved in the hydrostatic skeleton of nematodes and annelids?

Answer 3

• Longitudinal muscles
• Circular muscles

These muscle layers act antagonistically to aid in locomotion and maintain shape.

Question 4

What is an exoskeleton?

Answer 4

A rigid outer covering of the body that acts as a skeleton

Different types include chitinous, calcium carbonate, and bony plates.

Question 5

What is the main component of the chitinous exoskeleton found in arthropods?

Answer 5

Chitin

The chitinous exoskeleton is often hardened by proteins or calcium carbonate.

Question 6

What are the types of endoskeletons found in the animal kingdom?

Answer 6

• Plates of calcium carbonate (in echinodermates)
• Bones
• Cartilage (in chordates)

Endoskeletons are buried in the soft tissues of the animal.

Question 7

List the common functions of skeletal systems in animals.

Answer 7

• Support
• Protection
• Movement

Skeletons provide a rigid framework, protect internal organs, and allow for movement.

Question 8

What are the functions of the human skeletal system?

Answer 8

• Support
• Protection
• Movement
• Storage and release of calcium
• Storage and release of phosphates
• Production of blood cells

These functions are influenced by various hormones.

Question 9

How do animals swim?

Answer 9

• Using legs as oars (e.g., insects)
• Jet propulsion (e.g., squids)
• Moving body and tail side to side (e.g., fishes)
• Undulating body and tail up and down (e.g., whales)

Fusiform body shape is a common adaptation for fast swimming.

Question 10

What is the primary method of movement for animals through air?

Answer 10

Flying

Flying animals use wings to lift their bodies against gravity, and wings act as airfoils.

Question 11

What shape helps to reduce drag force in flying animals?

Answer 11

Fusiform shape of the wings

This shape alters air currents to assist in flight.

Question 13

The human skeleton is divided into two main parts: ________ and ________.

Answer 13

• Axial skeleton
• Appendicular skeleton

The axial skeleton consists of the skull, vertebral column, sternum, and ribs, while the appendicular skeleton consists of girdles and limb bones.

Question 14

The axial skeleton consists of which components?

Answer 14

• Skull
• Vertebral column
• Sternum
• Ribs

These components form the central axis of the human body.

Question 15

The appendicular skeleton consists of which components?

Answer 15

• Pectoral girdle
• Pelvic girdle
• Limb bones

These components facilitate movement and support the limbs.

Question 16

The human skull consists of how many bones?

Answer 16

21

Most of these bones are connected by ossified joints called sutures.

Question 17

The skull is divided into two main parts: ________ and ________.

Answer 17

• Cranium
• Face

The cranium protects the brain, while the facial bones form the structure of the face.

Question 18

Name the bones that make up the cranium.

Answer 18

• Frontal bone
• Two parietal bones
• Occipital bone
• Two temporal bones
• Ethmoid bone
• Sphenoid bone

These bones collectively protect the brain and support facial structures.

Question 19

The facial bones include which of the following?

Answer 19

• Two zygomatic bones
• Maxilla
• Two nasal bones
• Two lacrimal bones
• Vomer
• Two palatine bones
• Two inferior conchae
• Mandible

These bones contribute to the structure of the face and support the teeth.

Question 20

What is the human cranial capacity?

Answer 20

Nearly 1.5 L

This capacity indicates the volume of the cranial cavity that houses the brain.

Question 21

The foramen magnum is located on the inferior surface of the cranium and provides passage for the _______.

Answer 21

spinal cord

This opening allows the spinal cord to connect with the brain.

Question 22

The occipital condyles articulate with which vertebrae?

Answer 22

Atlas vertebrae

This articulation permits nodding movements of the head.

Question 23

What are fontanelles in the human skull?

Answer 23

Soft membranous regions

They allow slight compressions at birth and are replaced by bones within 1-2 years.

Question 24

The sutures in the skull are what type of joints?

Answer 24

Immovable joints

These joints provide additional protection to the brain.

Question 25

What are **sinuses**?

Answer 25

Air-filled cavities lined by ciliated mucous membrane ## Footnote They communicate with the nasal cavity and help reduce the weight of the skull.

Question 26

The **maxilla** is fused with the cranium, while the **mandible** is _______.

Answer 26

movable ## Footnote This allows for the movement necessary for chewing.

Question 27

The **zygomatic arch** is formed from parts of which bones?

Answer 27

* Zygomatic bone * Temporal bone ## Footnote This structure provides a surface for muscular attachment for moving the lower jaw.

Question 28

The **lower jaw** contains which two processes?

Answer 28

* Condyloid process * Coronoid process ## Footnote The condyloid process articulates with the temporal bone, while the coronoid process provides attachment for muscles.

Question 29

The **temporal bone** contains which three processes?

Answer 29

* Zygomatic process * Mastoid process * Styloid process ## Footnote These processes provide surfaces for muscle attachment.