Endocrinology and Bone Growth Quiz

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Questions and Answers

What condition results from Vitamin C deficiency in both children and adults?

Osteoporosis

Dwarfism

Rickets

Scurvy (correct)

Which hormone increases general tissue growth, including bone growth?

Insulin

Growth hormone (correct)

Estrogen

Thyroid hormone

Which condition is characterized by excessive secretion of growth hormone?

Dwarfism

Scurvy

Gigantism (correct)

Hypothyroidism

What role do estrogen and testosterone play during puberty?

Close the epiphyseal plate and increase bone growth Signup and view all the answers

What is the first stage of bone remodeling?

Resorption Signup and view all the answers

What is formed when a bone is broken and blood vessels in the bone are damaged?

Hematoma Signup and view all the answers

What process is essential during long-bone growth to maintain normal proportions and strength?

Bone remodeling Signup and view all the answers

What occurs during the 'formation' stage of bone remodeling?

Osteoblasts synthesize a matrix to replace resorbed bone Signup and view all the answers

What type of movement decreases the angle of a joint and brings two bones closer together?

Flexion Signup and view all the answers

Which movement is characterized by moving a limb away from the midline of the body?

Abduction Signup and view all the answers

What is the term for the combination of flexion, extension, abduction, and adduction in a circular motion?

Circumduction Signup and view all the answers

During which movement do the radius and ulna become parallel and the palm faces anteriorly?

Supination Signup and view all the answers

Inversion of the foot is defined as turning the sole in which direction?

Medially Signup and view all the answers

What characterizes a comminuted fracture?

It breaks the bone into multiple fragments. Signup and view all the answers

What stimulates osteoclast activity to increase blood calcium levels?

Secretion of parathyroid hormone (PTH). Signup and view all the answers

Which type of cartilage provides sturdy support with some flexibility?

Hyaline cartilage. Signup and view all the answers

How does calcitonin affect osteoclast activity?

It inhibits osteoclasts, reducing calcium release from bone. Signup and view all the answers

What is the primary function of osteoblasts?

To build new bone and store calcium. Signup and view all the answers

Which type of cartilage can withstand heavy compression?

Fibrocartilage. Signup and view all the answers

What initiates the secretion of parathyroid hormone (PTH)?

Decreased blood calcium levels. Signup and view all the answers

Which structure connects the ribs to the sternum?

Costal cartilage. Signup and view all the answers

What is the primary function of intervertebral discs?

To separate and cushion the vertebrae Signup and view all the answers

How many bones does an adult human typically have?

206 Signup and view all the answers

Which part of the axial skeleton primarily protects the brain?

Cranial vault Signup and view all the answers

What is the function of the foramen magnum?

To enable the spinal cord to join with the brain stem Signup and view all the answers

Which bone is referred to as the 'keystone bone' of the cranium?

Sphenoid bone Signup and view all the answers

Which bones form the superior and lateral aspects of the skull?

Parietal bones Signup and view all the answers

What structure allows cranial nerve II to pass to serve the eye?

Optic canals Signup and view all the answers

Which of the following describes the mandible’s connection to the skull?

It is attached by a movable joint. Signup and view all the answers

What separates the head from the shaft of the humerus?

Anatomical neck Signup and view all the answers

Which part of the ulna articulates with the humerus?

Trochlear notch Signup and view all the answers

How many carpal bones are in the wrist?

8 Signup and view all the answers

What is the location of the radius in relation to the ulna?

Lateral side Signup and view all the answers

Which of the following carpal bones is boat-shaped?

Scaphoid Signup and view all the answers

What forms the knuckles of the hand?

Metacarpals Signup and view all the answers

What describes the distal row of carpal bones from medial to lateral?

Hamate, Capitate, Trapezoid, Trapezium Signup and view all the answers

How many phalanges does the thumb (pollex) have?

2 Signup and view all the answers

Study Notes

Vitamin C Deficiency and Scurvy

Vitamin C deficiency in children and adults causes scurvy, characterized by ulceration and hemorrhage throughout the body.

Growth Hormone

Anterior pituitary's growth hormone increases overall tissue and bone growth.
Excessive growth hormone leads to gigantism.
Insufficient growth hormone results in dwarfism.

Thyroid Hormone

Essential for normal tissue growth, including cartilage.
Deficiency results in smaller individuals.

Estrogen and Testosterone

Stimulate bone growth and closure of the epiphyseal plate.
Levels dramatically increase during puberty.

Bone Remodeling

Continuous process involving osteoclasts removing bone and osteoblasts depositing new bone.
Responds to calcium ion levels in blood and muscle/gravity pull on skeleton.
Essential for maintaining bone proportions and strength during growth.
Leads to thicker bones and projections where muscles attach.

Stages of Bone Remodeling

Resorption: Osteoclasts remove bone (3-4 weeks).
Reversal: Mononuclear cells prepare the bone surface for osteoblasts.
Formation: Osteoblasts build new bone (3-4 months).
Resting: A prolonged period before a new cycle begins.

Bone Repair

Bone fractures damage blood vessels, forming a hematoma.
Blood vessels and cells invade the clot, forming fibrous connective tissue and cartilage to hold bone fragments together.

Fractures

Incomplete: Fracture traverses part of the bone.
Complete: Bone separates into at least two fragments.
Comminuted: Bone breaks into multiple fragments.

Calcium Homeostasis

Bone is a major calcium storage site.
Calcium movement into (osteoblasts) and out of (osteoclasts) bone regulates blood calcium levels.
Balanced osteoblast/osteoclast activity maintains calcium equilibrium.
Decreased blood calcium stimulates parathyroid hormone (PTH) secretion.
PTH stimulates osteoclasts, increases kidney reabsorption of calcium, and promotes vitamin D formation for intestinal calcium absorption.
Increased blood calcium stimulates calcitonin secretion from the thyroid, inhibiting osteoclasts and promoting osteoblast calcium uptake.

Cartilages of the Skeleton

Hyaline cartilage: Provides sturdy support with flexibility (most skeletal cartilages).
Elastic cartilage: More flexible than hyaline, tolerates bending (external ear, epiglottis).
Fibrocartilage: High tensile strength and compression resistance (intervertebral discs, knee joint).

Important Adult Skeletal Cartilages

Articular cartilages: Cover bone ends at movable joints.
Costal cartilages: Connect ribs to sternum.
Nasal cartilages: Support the external nose.
Intervertebral discs: Separate and cushion vertebrae.

Bone Count

Newborns: ~350 bones
Adults: 206 bones

Axial Skeleton

Skull, vertebral column, and thoracic cage.
Protects brain, spinal cord, heart, and lungs.

Skull

Sits atop the vertebral column.
Cranium (8 bones) & Facial bones (14 bones).
Bones joined by sutures except for the mandible (movable joint).

Cranium

Cranial vault (calvaria): Superior, lateral, and posterior skull walls.
Cranial base: Bottom of the skull.

Cranial Bones

Frontal bone: Forehead, superior orbit, anterior cranial fossa floor.
Parietal bones (2): Superior and lateral skull aspects.
- Temporal bones (2): Inferolateral skull; temples, external auditory meatus, zygomatic process.
Occipital bone: Posterior skull and base; foramen magnum.
Sphenoid bone: Keystone bone; articulates with all other cranial bones; parts of eye orbits; sella turcica (pituitary gland location); optic canals; foramen rotundum.

Humerus

Head separated from shaft by anatomical and surgical neck (fracture site).
Capitulum (articulates with radius).
Trochlea (articulates with ulna).

Forearm (Antebrachium)

Ulna (medial, little finger side); trochlear notch rotates over humerus.
Radius (lateral, thumb side); head rotates over humerus. Ulna and radius articulate with humerus at the elbow.

Hand (Manus)

Wrist (8 carpal bones in two rows).
Proximal row: Scaphoid (boat-shaped), lunate (moon-shaped), triquetrum (three-cornered), pisiform (pea-shaped).
Distal row: Hamate (hooked process), capitate (head-shaped), trapezoid (4-sided, parallel sides), trapezium (4-sided, no parallel sides).
Metacarpals (5 bones; palm; form knuckles).
Phalanges (digits; thumb has 2; fingers have 3).

Types of Body Movement

Flexion: Decreases joint angle.
Extension: Increases joint angle.
Rotation: Movement around a longitudinal axis.
Abduction: Movement away from midline.
Adduction: Movement towards midline.
Circumduction: Combination of flexion, extension, abduction, and adduction.
Supination: Forearm rotates laterally (palm anterior, radius & ulna parallel).
Pronation: Forearm rotates medially (palm posterior).
Opposition: Thumb movement.
Inversion: Sole turns medially.
Eversion: Sole turns laterally.
Dorsiflexion: Lifting foot towards shin.
Plantar flexion: Depressing the foot.

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Description

Test your knowledge on the effects of various hormones on bone growth and development. This quiz covers topics including Vitamin C deficiency, growth hormones, thyroid hormones, and the processes involved in bone remodeling. Challenge yourself and understand how these factors contribute to the overall skeletal health.