Exercise 8 Review Sheet the Axial Skeleton Vertebrae Ribsm Sternum Hyoid Answers

The centric skeleton is the department of a vertebrate'due south skeleton that comprises the caput and trunk bones. The human skeleton is fabricated up of 80 basic and is divided into six sections: the skull (22 bones), eye ear ossicles, hyoid os, rib muzzle, sternum, and spinal column. The centric and appendicular skeletons combine to produce the entire skeleton. The bones of the vertebrae, sacrum, coccyx, attic, ribs, and sternum are too known as the centric skeleton.

The brain and other of import organs are housed in flat bones. The centric skeletons of humans are the subject area of this article; nonetheless, it is vital to understand the axial skeleton'due south evolutionary lineage. The homo centric skeleton is fabricated up of 81 basic. Information technology is the body's medial core, connecting the pelvis to the trunk and housing the appendix skeleton. With the exception of the skull, the bones of the skeleton weaken as information technology ages. The brain is protected past the skull, which stays sturdy. On this page, permit us acquire everything about the centric skeleton in detail. Read further to discover more.

• What is a Man Skeletal System?
  • What is an Axial Skeleton?
  • Axial Skeleton Diagram
  • Axial Skeleton Components
  • Centric Skeleton Functions
  • Did you know?
  • Axial Skeleton and Appendicular Skeleton – Comparison
  • Summary
  • Frequently Asked Questions (FAQs) on Axial Skeleton

What is a Human Skeletal System?

The Human Skeletal Organisation consists of a framework of bones and a few cartilages to grade the endoskeleton in humans. This system has a meaning office in providing shape to the trunk and facilitates motion in combination with muscles.

The skeletal system of humans can be basically divided into 2 parts (i) the axial skeleton and (ii) the appendicular skeleton.

The centric skeleton constructs the central axis of the trunk, while the appendicular skeleton comprises the limbs and girdles.

What is an Axial Skeleton?

"Axial skeleton comprises 80 basic distributed along the main central centrality of the body. The skull, the vertebral cavalcade, sternum, and ribs constitute the axial skeleton." (Source: NCERT).

Definition: The bones of the limbs are attached to the centric skeleton via girdles. The axial skeleton forms the main frame of the torso in the longitudinal axis.

Centric Skeleton Diagram

Fig: The Axial Skeleton

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Axial Skeleton Components

The main components of centric skeleton are:

1. The Skull
2. The Vertebral Cavalcade
3. Thoracic Cage

Fig: Axial Skeleton Components

i. Skull: The skull is abony framework of the head that protects the encephalon. It acts equally a encompass to the brain and supports the structure of the face up. The ii parts of the skull are the cranium and facial basic. The skull of humans is said to be dicondylic. The skull consists of \(29\) basic, i.e. \(8\) in the attic, \(14\) in the face, \(vi\) ear ossicles and ane hyoid os.

(A) Cranium: This includes \(8\) bones: \(1\) Frontal bone, \(2\) Parietal os, \(two\) Temporal os, \(one\) Occipital os, \(1\) Sphenoid, and \(ane\) Ethmoid.

1. Frontal Os: Information technology is a flat bone that forms our forehead and the upper part of our eye sockets.
2. Parietal Bone: These are pairs of apartment bones present behind the frontal bones on either side of the caput.
3. Temporal Bone: This pair of irregular bones are present under the parietal bones on the lateral sides.
4. Occipital Bone: It is a flat bone present at the back of the skull. A large hole, the Foramen magnum, is at the base of the skull that allows the encephalon to continue into the spinal cord located at the dorsum.
5. Sphenoid Bone: It is an unpaired and irregular bone that lies below the frontal os and forms the low or cavity called sella turcica in which the pituitary gland is present. It forms the base of the skull, forms walls and floors of the orbit, and spans the width of the head to clear with other bones and provide rigidity to the construction of skull. Many muscles of mastication are also attached to the sphenoid bone.
6. Ethmoid Bone: The ethmoid bone is a pocket-size unpaired bone that divides the nasal cavity from the brain and is located in the midline of the anterior cranium.

Fig: Skull

(B) Facial Basic: This includes \(xiv\) bones: \(ii\) Zygomatic bone, \(2\) Lacrimal bone, \(2\) Nasal os, \(ii\) Inferior nasal conchae os, \(2\) Palatine, \(ii\) Maxilla, \(1\) Vomer, and \(one\) Mandible.

1. Zygomatic os: This pair of bones course the cheek of the face that articulates with sphenoid, temporal, and maxilla basic.
2. Lacrimal bone: These pairs of basic form the office of the medial wall of the orbit. They are the smallest bone on the confront.
3. Nasal os: These bones are 2 slender bones located at the front end of the nose.
4. Junior nasal conchae: These are two bones located in thenasal cavity; they increase the surface of the nasal cavity and thus increase the amount of air that can run across cavity walls.
5. Palatine: These pairs of bones are located at the back of the oral crenel and make part of the hard palate.
6. Maxilla: These are 2 bones comprised ofthe upper jaw andhard palate.
7. Vomer: It makes the rear side of the nasal septum.
8. Mandible: The mandible is the lower jawbone. This articulates with the temporal basic at the temporomandibular joints.

(C) Hyoid Os: It is a U-shaped bone that is not fastened to any other bone. Instead, it is a single os present in the cervix between the lower jaw and the soundbox. It supports the tongue and provides insertion to some tongue muscles.

(D) Ear Ossicles:The ear ossicles are minor, flexible chains of three small bones, called Malleus (Hammer),Incus (Anvil), andStapes (Stirrup), which amplifies the sound waves in eye ear.

ii. Vertebral Column: It forms the main framework of the body, and it is known as the backbone or spine. It stretches from the base of operations of the skull to the pelvis. The vertebral column in adults consists of \(33\) bones arranged serially called vertebrae. In adults it includes \(7\) Cervical vertebrae, \(12\) Thoracic vertebrae, \(five\) Lumbar vertebrae, \(5\) Fused Sacral vertebrae, and \(4\) Fused Coccygeal vertebrae. The human developed vertebral formula is \({{\rm{C}}_7}\;{{\rm{T}}_{12}}\;{{\rm{Fifty}}_5}\;{{\rm{S}}_{(5)}}{{\rm{C}}_{(4)}}\)_.

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1. Cervical: Cervical vertebrae are \(7\) in number. They are nowadays in the neck region. The Atlas is the first cervical vertebrae and the Axis is the second cervical vertebrae. It is located right below the skull, and is attached to the skull with the aid of condyles.
2. Thoracic: Thoracic vertebrae are \(12\) in number. It forms the vertebral spine and it supports the rib cage. It is present on the dorsal side of the thorax region and forms the dorsal part of the thoracic muzzle.
3. Lumbar: Lumbar vertebrae are 5 in number. They form the dorsal role of the abdomen, i.eastward. lower back. They are the largest and the strongest vertebrae.
4. Sacral: The five Sacral vertebrae are fused in the adult, forming one structure chosen the Sacrum, and articulates with the innominate bones of the pelvic girdle. In females, the sacrum is shorter and wider than the males.
5. Coccygeal: The four Coccygeal vertebrae are fused to form a curved triangular bone, called the coccyx. It is also known equally tailbone. Information technology is the terminal part of the vertebral cavalcade, and it ends in a triangle shape.

Fig: Vertebral Column

3. Thoracic Cage: Information technology is also called rib muzzle. The thoracic cage consists of ribs and the sternum. Information technology is a bony structure that protects the organs in the thoracic cavity. It includes \(25\) bones, i.east., \(i\) sternum and \(24\) ribs.

A. Ribs: They are a cage-like formation of thin, apartment and curved bones. Ribs are mainly of iii types:

1. True ribs: The first vii pairs are fastened directly to the sternum.
2. False ribs: The 8^thursday, 9^th, and \({{\rm{10}}^{{\rm{thursday}}}}\) pairs of ribs are fused with \({{\rm{7}}^{{\rm{th}}}}\) rib, which in turn connect to the sternum.
3. Floating ribs: The \({{\rm{xi}}^{{\rm{th}}}}\) and the \({{\rm{12}}^{{\rm{th}}}}\) pair of ribs are not attached to the sternum at all and remain free.

B. Sternum: The sternum is also known as breastbone, and it is the long flat os present in the midline of the thorax. It provides the joint site for true ribs and pectoral girdle basic.

Fig: Thoracic Muzzle

Axial Skeleton Functions

The functions of Axial Skeleton are:

Components of Centric Skeleton	Role
Skull	Information technology provides protection to the encephalon, forms the orbit of the eyes, attachment to muscles, and structure to face.
Vertebral Column	It provides protection to the spinal cord and supports the head. It provides articulation sites for ribs and innominate basic of pelvic girdle. It is as well responsible for flexibility of the back.
Thoracic Cage	It protects and supports the internal organs of the body such as heart and lung and some of the abdominal organs like kidney and liver.

Did you lot know?

1. Stapes are the smallest bones in our body. Information technology is located in the middle ear.
2. Hyoid is the only bone which is not connected to any other bone.

Axial Skeleton and Appendicular Skeleton – Comparing

Comparison Parameter	Axial Skeleton	Appendicular Skeleton
Definition	The office of the skeleton that consists of the bones of skull, the vertebral cavalcade, the sternum, and the rib cage.	The portion of the skeleton that consists of the bones of the pectoral girdle, the pelvic girdle, the upper limbs, and the lower limbs.
Formation	It forms the central axis of the homo body.	Information technology is associated with the appendages of our torso.
No of Basic	At that place are \(fourscore\) bones in the axial skeleton.	There are \(126\) bones in appendicular skeleton
Office	It supports the posture, stability, and residue of the body.	It helps in movement and digital manipulation.

Fig: Comparing of Axial and Appendicular Skeleton

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Summary

The axial skeleton is a part of the human skeleton, comprising the skull, vertebral column, and thoracic cage. The axial skeleton protects the brain, spinal cord, eye, lungs, and kidneys. It provides structural support and provides articulation sites to the appendicular skeleton. The axial and appendicular skeleton together make a complete homo skeleton. The centric skeleton is a combination of \(eighty\) bones.

Oftentimes Asked Questions (FAQs) on Axial Skeleton

Q.1. What bones are in the axial and appendicular skeleton?
Ans: The axial skeleton forms the vertical axis of the torso and includes the bones of the head, neck, back, and chest of the torso. It consists of \(eighty\) bones that include the skull, vertebral column, and thoracic cage. The appendicular skeleton consists of \(126\) bones and includes all bones of the pectoral girdle, the upper limbs, the pelvic girdle, and the lower limbs.

Q.2. What are the centric skeleton parts?
Ans: Axial skeleton can be divided into three parts: the skull, vertebral column, & the rib cage or thoracic cage.

Q.3. Where is the axial skeleton located?
Ans: The axial skeleton lies along the central longitudinal centrality of the human torso.

Q.4. Are ribs centric or appendicular?
Ans: Axial skeleton includes the bones of the skull, vertebrae, thoracic muzzle, hyoid os and ear ossicles. Ribs and sternum are part of the thoracic muzzle. So, ribs are part of the axial skeleton.

Q.5. What are the functions of the axial skeleton?
Ans: The functions of the centric skeleton are:

1. Skull provides protection to the brain, forms the orbit of the optics and provide structure to the face up.
2. The vertebral cavalcade provides protection to the spinal cord and supports the head. It allows flexibility of the dorsum and trunk.
3. The thoracic cage protects and supports the internal organs of the body such equally the centre and lungs and some of the intestinal organs similar the kidney and liver.

At present that you have a detailed article on Axial Skeleton, we hope you set up well. Exercise let us know if y'all become stuck in the comments section and we will get back to you every bit soon as possible.

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