Movement Rib Bone: Biology Practical Preparation Towards NECTA Exams (CSEE)
MOVEMENT Rib Bone
Distinctive characteristics of rib bones
1. Curved Shape: They possess a unique curved or arc-shaped structure.
2. Pairs: They are typically found in pairs on both sides of the vertebral column.
3. Articulation Points: They have articulation points at one end for attachment to the thoracic vertebrae and costal cartilages at the other end, often connected to the sternum or adjacent ribs.
4. Flat and Thin: They are flat and relatively thin bones, in contrast to cylindrical long bones.
5. Ridges and Grooves: They display ridges and grooves on their outer surface, which serve as muscle attachment sites.
6. Size and Length: They are relatively long bones compared to some others in the skeleton.
7. Position in the Skeleton: They are located in the thoracic region, extending from the spine to the anterior chest.
8. Countable Pairs: They exist in pairs, with humans typically having 12 pairs (24 ribs in total).
Functions of Rib Bones:
1. Protection: Rib bones protect vital organs in the chest cavity, including the heart and lungs, from external impacts.
2. Support: They provide structural support to the chest, helping maintain its shape and integrity.
3. Attachment for Muscles: Rib bones serve as attachment points for various muscles, including those involved in breathing and chest movement.
4. Respiratory Muscle Attachment: Muscles such as the intercostal muscles attach to the ribs and play a direct role in expanding and contracting the chest during breathing.
5. Movement Facilitation: They assist in the flexibility and mobility of the chest wall during inhalation and exhalation.
6. Contribution to Posture: Rib bones contribute to maintaining an upright posture and stability of the upper body.
Movement Rib Bone: Biology Practical Preparation Towards NECTA Exams (CSEE)
Contribution of the rib bone to Respiratory Processes:
1. Expansion of Chest: During inhalation, the contraction of the diaphragm and intercostal muscles causes the rib cage to expand, elevating the rib bones.
2. Increased Thoracic Volume: The upward and outward movement of rib bones increases the volume of the thoracic cavity.
3. Pressure Changes: As thoracic volume increases, the pressure inside the chest decreases, creating a pressure gradient for air to flow into the lungs.
4. Lung Expansion: The expansion of rib bones allows the lungs to expand as well, drawing air into the alveoli.
5. Exhalation: During exhalation, the relaxation of the muscles lowers the rib cage, reducing thoracic volume and increasing pressure, leading to the expulsion of air from the lungs.
6. Efficient Breathing: The coordinated movement of rib bones and associated muscles ensures efficient inhalation and exhalation, facilitating the exchange of oxygen and carbon dioxide in the respiratory process.
Describe how rib bones articulate with the thoracic vertebrae and the sternum.
Thoracic Vertebrae Articulation:
1. The posterior or dorsal end of each rib bone articulates with a corresponding thoracic vertebrae in the vertebral column.
2. There are 12 pairs of ribs in humans, and each rib bone attaches to the vertebral column at a specific thoracic vertebra. For example, the first rib attaches to the first thoracic vertebra (T1), the second rib to the second thoracic vertebra (T2), and so on.
3. The articulation point on the rib bone includes the head of the rib, which has facets that fit into the costal facets on the vertebral bodies and transverse processes of the thoracic vertebrae.
4. These articulations allow for the flexibility and mobility of the rib cage during respiration.
1. The anterior or ventral end of most rib bones articulates with the sternum (breastbone).
2. The attachment to the sternum is via costal cartilages, which are flexible cartilaginous extensions at the anterior end of each rib.
3. The first seven pairs of ribs (true ribs) have direct cartilaginous connections to the sternum, making them “vertebrosternal” ribs. The cartilages of these ribs connect directly to the sternum.
4. The next three pairs (false ribs) have indirect connections to the sternum, with their cartilages either attaching to the cartilage of the rib just above or joining together before attaching to the sternum.
5. The last two pairs (floating ribs) have no direct attachment to the sternum and terminate freely in the abdominal muscles.
Types of Ribs:
Explain the differences between true ribs, false ribs, and floating ribs, and how they are numbered.
True Ribs, False Ribs, and Floating Ribs differ in their attachment to the sternum and how they are numbered:
- Attach directly to the sternum via individual costal cartilages.
- Numbered as the first seven pairs (ribs 1-7).
- Provide structural support and protection to the chest cavity.
1. Indirectly attach to the sternum via shared or connecting cartilages.
2. Include pairs 8-10 (ribs 8-10).
3. Ribs 8-9 have their cartilages attached to the cartilage of the rib just above.
4. Rib 10 has its cartilage that attaches to the cartilage of the rib just above and often joins with rib 9’s cartilage.
5. Offer less direct support to the sternum but contribute to chest wall integrity.
1. Lack direct attachment to the sternum.
2. Comprise the last two pairs, ribs 11 and 12.
3. Their costal cartilages do not connect to the sternum or to other ribs.
4. Provide minimal structural support but protect the kidneys and flank area.
Tibia and Fibula:
How can you distinguish between the tibia and fibula when examining these bones?
1. Larger and stronger of the two leg bones.
2. Located on the inner side (medial) of the lower leg.
3. Proximal (upper) end forms the medial condyle, which articulates with the femur.
4. Distal (lower) end forms the medial malleolus, which is the inner ankle bone.
5. Weight-bearing bone of the lower leg.
1. Slimmer and more delicate compared to the tibia.
2. Located on the outer side (lateral) of the lower leg.
3. Proximal end articulates with the tibia but doesn’t bear significant weight.
4. Distal end forms the lateral malleolus, which is the outer ankle bone.
5. Serves as an attachment point for muscles and ligaments but doesn’t bear as much weight as the tibia.
Describe how the tibia articulates with the femur at the knee joint and with the fibula.
The tibia articulates with the femur at the knee joint and with the fibula at two distinct joints, the proximal and distal tibiofibular joints:
Tibia Articulation with the Fibula:
Proximal Tibiofibular Joint:
1. At the proximal (upper) end of the tibia and fibula, there is a synovial joint known as the proximal tibiofibular joint.
2. Here, the head of the fibula articulates with a facet on the lateral aspect of the tibia.
3. The joint provides minimal movement and serves mainly for stability.
Distal Tibiofibular Joint (Syndesmosis)
1. The distal (lower) ends of the tibia and fibula are connected by strong ligaments, forming a fibrous joint called the distal tibiofibular joint or syndesmosis.
2. Unlike the proximal joint, the distal tibiofibular joint allows for little to no movement and primarily serves as a point of stability.
3. This joint is crucial for maintaining the alignment of the tibia and fibula in the lower leg and for stability of the ankle joint.
This is a long bone on the upper part of the hind limb (on the thigh region)
1. The head of femur fits in the pelvic girdle to form hip joint
2. It articulates with tibia at lower end to form knee joint
3. It provides surface for the attachment of leg muscles and it supports the thigh.
Functions of femur
1. Femur provides the surface area for the attachment of leg muscles
2. It provides the site for articulation with the pelvic girdle
3. It supports the thigh.
Adaptations of Femur
1. It is long to provide the surface area for attachment of thigh muscles
2. It has a rounded head which articulates with acetabulum of pelvic girdle to allow flexible movement of the leg
3. It has condyles for articulation with patella to allow movement in one plane.
Briefly explain the femur articulation
The femur, the thigh bone, articulates with two major joints in the human body:
1. The proximal (upper) end of the femur articulates with the acetabulum, which is a concave socket in the hip bone (part of the pelvis).
2. This ball-and-socket joint allows for a wide range of motion, including flexion (bending the hip), extension (straightening the hip), abduction (moving the thigh away from the midline), adduction (moving the thigh toward the midline), and rotation of the thigh.
3. The articulation between the femoral head and the acetabulum is stabilized by ligaments and muscles, providing both mobility and stability to the hip joint.
1. The distal (lower) end of the femur articulates with the tibia and patella (kneecap) to form the knee joint.
2. This hinge joint allows primarily for flexion (bending) and extension (straightening) of the lower leg. The patella articulates with the femur and aids in extending the knee.
3. The femoral condyles, located at the distal end of the femur, fit into corresponding tibial condyles to create the knee joint.
4. Ligaments, including the anterior and posterior cruciate ligaments and the medial and lateral collateral ligaments, provide stability to the knee joint.
Radius and Ulna:
How can you distinguish between the radius and ulna when examining these bones?
You can distinguish between the radius and ulna when examining these bones by considering the following features:
1. Location: The radius is located on the lateral (thumb) side of the forearm when the palm is facing upward
2. Shape: It is relatively straight and slender in shape.
3. Length: The radius is usually shorter than the ulna.
4. Proximal End: The proximal (upper) end of the radius has a round head that articulates with the capitulum of the humerus, forming the radiocarpal joint (wrist joint).
5. Styloid Process: The distal (lower) end of the radius has a pointed styloid process that extends toward the wrist and provides stability to the joint.
6. Articulation with Ulna: The radius articulates with the ulna at the proximal and distal radioulnar joints, allowing for rotational movements of the forearm.
1. Location: The ulna is located on the medial (pinky finger) side of the forearm when the palm is facing upward.
2. Shape: It has a more pronounced curvature, with a longer shaft compared to the radius.
3. Length: The ulna is usually longer than the radius.
4. Proximal End:The proximal (upper) end of the ulna has an olecranon process, which forms the bony prominence at the back of the elbow joint. This process fits into the olecranon fossa of the humerus, allowing for the extension of the forearm.
5. Styloid Process: The distal (lower) end of the ulna has a slightly curved styloid process that contributes to the stability of the wrist joint.
6. Articulation with Radius:
The ulna articulates with the radius at the proximal and distal radioulnar joints, facilitating forearm rotation.
Functions of Radius and Ulna
- They support the carpals, metacarpals and phalanges.
- They provide the surface for attachment of muscles of the arm
Adaptations of Radius and Ulna
1. They are long to provide the large surface area for attachment of the muscles of the forearm
2. Ulna has olecranon process with sigmoid notch for articulation with the trochlea of the humerus to form a hinge joint at the elbow.
3. Distal articulating surface is lined with cartilage for articulation with carpals.
1. Are found in the chest region, they are 12 vertebrae. The thoracic vertebrae with the ribs and sternum form the thoracic cage.
2. The main role of the thoracic cage is to protect the heart, lungs and major blood vessels also plays major role on breath movement
Distinctive Features of Thoracic Vertebrae
1. They have a long neural spine, usually pointing backwards
2. They have circular-shaped neural canals
Functions of Thoracic Vertebrae
They support the ribs by providing articulation.
Adaptations of Thoracic Vertebrae
1. They have long neural spine which provide large surface area for attachment of back muscles
2. They have strong centrum for support of body weight and support vertebral column for attachment with ribs
3. They have facets for articulation with the ribs
4. They have pre- and post-zygapophysis for articulation with adjacent vertebrae
5. They have wide neural canal for passage of spinal cord.
Humerus is a long bone of the upper arm.
1. It has a rounded head which articulates with the glenoid cavity of the scapula forming a ball and socket joint.
2. It has two rounded projections near the head called the Greater and Lesser tuberosities.
3. Between the greater and lesser tuberosities, there is a depression called Bicipital groove.
4. Its lower end articulates with the Radius and Ulna to form a hinge joint at the elbow.
Adaptations of Humerus
1. Humerus has bicipital groove through which tendons of the biceps muscles pass.
2. It is long to provide large surface area for attachment of biceps and triceps muscles
3. It has trochlea at the lower end for articulation with forearm to form a hinge joint at the elbow which allows movement in one plane.
You have been provided with mammal’s bone A, B, C and S, T, U of fore limb and hind limb. Examine carefully and answer the following questions.
1. Identify each bone A, B, C and S, T, U by their names
2. Mention the bones which are of fore limb and hind limb
3. Give the main function of the bones S, T and U
4. How each bone S, T and U adapted to its function?
5. Name the various joints formed between bone A, B and C
6. Using diagrams show the structures of various bones that you have observed.
7. What are the structural differences between bone B and C?
8. Give any four bones in which red blood cells are formed.
9. What is the name of the softy and fatty tissue inside of the bone S, T and U?
10. What is the name and functions of long protrusion at the end of bone C?
11. You have been provided with bone bones X and Y
Observe carefully and answer the following questions
1. Give the name of bones provided
2. Give the function of bone X
3. What are the adaptations of bone X to its function?
4. Draw a well labelled diagram of bones X and give the functions of the labelled parts
5. How many pieces of bone Y comprises in the body of mammals?
6. There are three types of bone Y in mammals name them with their meaning
7. Why bone why also known as thoracic ribcage?
8. What are the main functions of bone Y?