A&P 1 Test 3 (Bio 102) Flashcards
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5 Functions of the skeletal system
Support
Protection
Movement
Storage
Blood Cell Production
4 components of the skeletal system
Bones - 206
Cartilage - Cushions Joints…nose and ears
Ligaments - Connects Bones to Bones
Tendons - Attach muscles
How many bones are in the human body
206
What does cartilage do?
Cushions joints and supports structures like the nose and ears.
What do ligaments do?
Connect bones to other bones at joints.
What do Tendons do?
Attach muscles to bones
Which heals easily (by comparison) Ligaments or Tendons?
Tendons - better blood flow
5 Classifications of bones (types of bones)
Long
Short
Flat
Irregular
Sesamoid
Example of Long Bones
Longer than wide (so finger bones are “long”)
Used for movement
Femur and Humerus, etc…
Example of Short Bones
(Cube-shaped, provide stability, support)
Carpals
Tarsals
Example of Flat Bones (3)
(Thin and protect organs, sites of muscle attachment)
skull, ribs, sternum
Example of Irregular Bones
(Complex shapes, Serve various functions)
vertebrae
pelvis
Example of Sesamoid Bones
(Form within tendons to protect them)
Patella
Anatomy of the long bone
(6 parts - D.E.M.M.P.E)
Diaphysis: Shaft of the bone.
Epiphysis: Ends of the bone (proximal and distal).
Metaphysis: Region between diaphysis and epiphysis, contains the growth plate.
Medullary cavity: Hollow area inside diaphysis containing yellow marrow.
Periosteum: Outer fibrous covering.
Endosteum: Thin membrane lining the medullary cavity.
Define Diaphysis
Shaft of the bone.
Define Epiphysis
Ends of the bone (proximal and distal)
Define Metaphysis
Region between diaphysis and epiphysis, contains the growth plate.
Define Medullary Cavity
Hollow area inside diaphysis containing yellow marrow.
Define Periosteum
Outer fibrous covering
Define Endosteum
Thin membrane lining the medullary cavity
Compact Bone has ___________
Thin outer layers
Spongy Bone description
Central spongy bone contains red marrow
Scientific Words for bony parts
F.T.C.F.C.P.T.M.S.S.
Foramen
Tuberosity
Condyle
Fossa
Crest
Process
Trochanter
Meatus
Sinus
Sulcus
Foramen
Hole in a bone for passage of nerves/blood vessels (e.g., foramen magnum in skull).
Tuberosity
Rough projection for muscle attachment (e.g., tibial tuberosity).
Condyle
Rounded articular surface (e.g., occipital condyles).
Fossa
Shallow depression (e.g., olecranon fossa on humerus).
Crest
Narrow ridge (e.g., iliac crest).
Process
Projection for attachment (e.g., mastoid process of the skull).
Meatus
Canal-like passage (e.g., external auditory meatus).
Sinus
Cavity within a bone (e.g., frontal sinus)
Sulcus
Groove (e.g., intertubercular sulcus of humerus).
Trochanter
Large blunt projection (e.g., greater trochanter of femur).
Types of osseous tissue (3)
Osteoblasts
Osteoclasts
Osteocytes
Osteoblasts
Bone-building cells, secrete bone matrix
Osteocytes
Mature bone cells that maintain the bone matrix.
Bone cells (Osteo…) from monocyte stem cells and squamous stem cells
Osteoclasts
Osteoblasts
Composition of bones: Chemical (Organic and Inorganic parts)
Organic: Collagen fibers provide flexibility.
Inorganic: Hydroxyapatite (calcium phosphate) provides strength and hardness.
Composition of bones: Structural (Compact and Spongy)
Compact bone: Dense, provides strength.
Spongy bone: Lightweight, houses marrow.
Osteon (Compact Bone)
Each osteon has a central canal with blood vessels and nerves.
Lamellae (Compact Bone)
Concentric rings around the central canal.
Lacunae (Compact Bone)
House osteocytes, connected by tiny canals called canaliculi.
Canaliculi (Compact Bone)
Small Channel or duct
Anatomy of Spongy bone
Composed of ____
Filled with ____
Composed of trabeculae (thin, needle-like pieces of bone).
Spaces between trabeculae are filled with red marrow.
2 types of bone coverings
periosteum and endosteum
Periosteum
Dense fibrous membrane covering the outside of bones
Periosteum Functions
Protection.
Attachment point for tendons/ligaments.
Contains nerves and blood vessels for nourishment.
Endosteum
Thin membrane lining the medullary cavity
Endosteum functions
Involved in bone growth and repair.
Contains osteoblasts and osteoclasts for remodeling.
2 types of ossification
Intramembranous and Endochondral
Intramembranous ossification
Forms flat bones (e.g., skull, clavicle).
Mesenchymal cells differentiate into osteoblasts, which form bone directly without a cartilage model.
Endochondral ossification
Forms most bones (e.g., long bones).
Hyaline cartilage is replaced by bone over time.
Osteoblasts build bone on the cartilage scaffold.
4 Hormones affecting bones and their effects
Parathyroid hormone (PTH)
Calcitonin
Growth hormone
Thyroid hormones
Parathyroid hormone (PTH)
Increases blood calcium by stimulating osteoclasts.
Calcitonin
Release when blood calcium is high. Lowers blood calcium by inhibiting osteoclasts and stimulating osteoblasts.
Growth hormone
Stimulates bone growth during childhood.
Thyroid hormones
Regulate bone growth and metabolism.
Estrogen and Testosteron both do what…. and …. what happens to bones after menopause?
Estrogen and testosterone: Promote bone growth during puberty and lead to the closure of epiphyseal plates (stopping bone lengthening). After menopause, a decline in estrogen can lead to increased bone resorption and osteoporosis.
4 Conditions for normal bone growth
Adequate nutrients (calcium, vitamin D, phosphorus).
Proper hormone levels (growth hormone, thyroid hormones, sex hormones).
Mechanical stress (exercise, physical activity).
Good blood supply.
Bones grow in length (longitudinal) by….
Occurs at the epiphyseal plates via endochondral ossification. Cartilage grows on the epiphyseal side, and bone replaces cartilage on the diaphyseal side.
Bones grow in width (appositional)
Osteoblasts add bone tissue to the outer surface of the bone, while osteoclasts remove bone from the inner surface to maintain the medullary cavity.
Epiphyseal plates
Growth plates made of cartilage, present in growing children.
Epiphyseal lines
Remnants of the growth plates after they close during adulthood, indicating no further growth in length.
Effects of exercise and stress on bone
Weight-bearing exercises increase bone density by stimulating osteoblasts.
Lack of activity leads to bone loss (atrophy).
Bones remodel in response to mechanical stress (Wolff’s Law).
Wolff’s Law
Bones remodel in response to mechanical stress
Hematoma formation
Blood clot forms at the fracture site.
Fibrocartilaginous callus
Soft callus forms as cartilage fills the break.
Bony callus formation
Osteoblasts replace the cartilage with spongy bone
Bone remodeling
Osteoclasts remove excess bone, and compact bone is laid down.
Effects of aging on the skeletal system
Bone mass decreases
Joints stiffen, and cartilage becomes less resilient.
Fractures become more common, and healing slows down.
Osteopenia
Reduced bone density
Osteoporosis
Causes bones to become weak and brittle
Function of Axial Skeleton
Protects organs (brain, spinal cord, thoracic organs) and provides a central framework.
Function of Appendicular Skeleton
Facilitates movement and includes the limbs and girdles (pectoral and pelvic).
Intramembranous ossification process
Occurs in flat bones.
Mesenchymal cells differentiate into osteoblasts, which secrete bone matrix.
Osteocytes form as the matrix hardens, and compact bone forms around the spongy bone center.
Lordosis
Inward curvature of the spine, typically found in the lumbar region
Kyphosis
Outward curvature, often in the thoracic region, causing a “hunched” back appearance.
Scoliosis
Lateral (sideways) curvature of the spine, which can lead to a twisted posture if severe.
Which Spinal Curve is abnormal
Scoliosis
Blood calcium levels are tightly regulated by what system
the endocrine system.
Parathyroid hormone (PTH)
Released when blood calcium levels drop
Stimulates osteoclast activity to break down bone and release calcium into the bloodstream.
It also increases calcium absorption in the intestines and reduces calcium excretion by the kidneys.
Vitamin D
Enhances calcium absorption in the intestines, which indirectly affects calcium levels in the blood.
Skull: Occipital Bone Landmark
Foramen magnum: Large opening where the spinal cord exits the skull.
Skull: Occipital Bone Articulates with…
The atlas (C1 vertebra)
Skull: Occipital Bone Function
Allows the connection between the brain and spinal cord; the articulation with the atlas enables head nodding (yes motion)
Skull Temporal Bone Landmark
Mastoid process: A projection behind the ear that provides an attachment point for muscles like the sternocleidomastoid
Skull Temporal Bone Articulates with…
Mandible (at the temporomandibular joint or TMJ).
Skull Temporal Bone Function
Supports jaw movement and attachment of neck muscles.
Skull Sphenoid Bone Landmark
Sella turcica: A saddle-shaped depression that houses the pituitary gland.
Skull Sphenoid Bone Articulates with…
Frontal, parietal, temporal, and ethmoid bones.
Skull Sphenoid Bone Function
Provides structural support to the cranial cavity and houses the pituitary gland.
Skull Zygomatic Bone Landmark
Zygomatic arch: Formed by the zygomatic bone and the temporal bone, this structure gives shape to the cheek.
Skull Zygomatic Bone articulates with…
Maxilla, temporal, frontal, and sphenoid bones.
Skull Zygomatic Bone Function
Provides the structure of the face and forms part of the orbit.
Cervical Vertebrae (C1-C7) Landmark
Transverse foramen (only in cervical vertebrae): Allows passage of the vertebral arteries to the brain.
Cervical Vertebrae (C1-C7) articulates with…
Adjacent vertebrae, the atlas (C1) articulates with the occipital bone.
Cervical Vertebrae (C1-C7) Function
Supports the head and allows for its movement, particularly at the atlas (C1) and axis (C2) joints.
Thoracic Vertebrae (T1–T12) Landmark
Costal facets: Small depressions on the vertebral body and transverse processes where ribs articulate.
Thoracic Vertebrae (T1–T12) Articulates with…
Ribs (at the costal facets)
Thoracic Vertebrae (T1–T12) Function
Supports the rib cage and provides attachment points for the ribs, allowing for the protection of thoracic organs.
Lumbar Vertebrae (L1–L5) Landmark
Large vertebral body: The lumbar vertebrae have large bodies to support the weight of the upper body.
Lumbar Vertebrae (L1–L5) Articulates with…
Intervertebral discs and adjacent vertebrae.
Lumbar Vertebrae (L1–L5) Function
Bears the majority of body weight and allows for movement such as flexion and extension.
Clavicle Landmark
Acts as a brace to keep the arm away from the thorax and allows for arm mobility.
Clavicle Articulates with…
Sternum (manubrium) and scapula (at the acromion).
Clavicle Function
Acts as a brace to keep the arm away from the thorax and allows for arm mobility.
Scapula Landmark
Glenoid cavity: Shallow socket that articulates with the head of the humerus
Scapula Articulates with:…
Clavicle and humerus (at the shoulder joint).
Scapula Function
Allows for a wide range of shoulder motion and serves as an attachment point for muscles.
Humerus Landmark
Olecranon fossa: Depression that receives the olecranon of the ulna when the arm is extended.
Humerus Articulates with…
Scapula (at the glenoid cavity) and ulna/radius (at the elbow joint).
Humerus Function
Supports arm movement and forms the upper arm’s structure.
Radius Landmark
Radial head: Disc-shaped top part that articulates with the humerus and ulna.
Radius Articulates with…
Humerus (capitulum) and ulna (radial notch and ulnar notch).
Radius Function
Helps in forearm rotation and movement at the elbow and wrist.
Ulna Landmark
Olecranon: The bony prominence at the elbow.
Ulna Articulates with…
Humerus (at the olecranon fossa) and radius.
Ulna Function
Forms the elbow joint and provides stability to the forearm.
Pelvic Girdle: Ilium Landmark
Iliac crest: The uppermost edge of the pelvis, where muscles attach.
Pelvic Girdle: Ilium Articulates with…
Sacrum (at the sacroiliac joint).
Pelvic Girdle: Ilium Function
Supports body weight when sitting and standing, and serves as an attachment point for muscles.
Pelvic Girdle: Ischium Landmark
Ischial tuberosity: The part of the pelvis that supports body weight when sitting.
Pelvic Girdle: Ischium Function
Provides support for sitting and muscle attachment.
Pelvic Girdle: Ischium Articulates with…
The pubis and ilium
Pelvic Girdle: Pubis Landmark
Pubic symphysis: Joint where the two pubic bones meet at the front of the pelvis.
Pelvic Girdle: Pubis Articulates with…
The opposite pubic bone and the ilium.
Pelvic Girdle: Pubis Function
Supports pelvic organs and allows for slight movement between the two halves of the pelvis.
Femur Landmark
Head of the femur: Round top part that fits into the acetabulum of the pelvis.
Femur Articulates with…
Pelvis (at the acetabulum) and tibia (at the knee joint).
Femur Function
Supports body weight and allows for movement of the leg.
Tibia Landmark
Tibial tuberosity: A bump on the front of the tibia, just below the knee, where the patellar ligament attaches.
Tibia Articulates with…
Femur (at the knee joint) and talus (at the ankle).
Tibia Function
Bears weight and forms the lower leg
Fibula Landmark
Lateral malleolus: The outer ankle bone.
Fibula Articulates with…
Tibia and talus
Fibula Function:
Provides stability to the ankle and serves as a muscle attachment site.
Bony landmarks serve various functions
Attachment sites for muscles, tendons, and ligaments (e.g., tuberosities, crests, processes).
Pathways for nerves and blood vessels (e.g., foramina, grooves).
Joints for articulation with other bones (e.g., condyles, facets).
Bones that make up the eye orbit
Frontal (roof of the orbit).
Maxilla (floor of the orbit).
Zygomatic (lateral wall).
Lacrimal (medial wall).
Ethmoid (medial wall).
Sphenoid (back of the orbit).
Palatine (small part of the medial wall).
Maxillary sinuses
Located in the maxilla (cheekbone area); largest sinuses, involved in voice resonance and lightening the skull.
Ethmoid sinuses
Located between the eyes, within the ethmoid bone; part of the drainage system for mucus.
Frontal sinuses
Located in the frontal bone above the eyes; lighten the skull and help with voice resonance.
Sphenoid sinuses
Located behind the nasal cavity, within the sphenoid bone; assists with drainage and lightening the skull.
Fetal Skull Posterior fontanel
Smaller, located at the junction of the parietal and occipital bones.
Fetal Skull Anterior fontanel
Largest, located at the junction of the frontal and parietal bones.
Fetal Skull:
has soft spots called fontanels that allow for the skull to be compressed during birth and accommodate brain growth during infancy.
Fetal Skull Mastoid and sphenoid fontanels
Located at the sides of the skull.
Sagittal suture
Between the two parietal bones, running from front to back.
Coronal suture
Between the frontal and parietal bones, running side to side.
Lambdoidal suture
Between the parietal bones and occipital bone, in the back of the skull.
Squamous suture
Between the parietal and temporal bones, on the sides of the skull.
How the skull changes from birth to childhood
Skull grows rapidly as the brain enlarges
Fontanels close by the age of 2
Facial bones bone grow slowly, mandible and maxilla continue to grow in adolescence.
Spinal curves Primary curves (present at birth)
Thoracic curve
Sacral curve
Spinal curves Thoracic curve
Outward curve of the upper back (kyphotic).
Present at birth
Spinal curves Sacral curve
Outward curve of the lower back
Present at birth
Spinal Curves Secondary curves (develop after birth)
Cervical curve
Lumbar curve
Spinal Curves Cervical curve
Inward curve that develops when a baby lifts its head (lordotic).
After birth
Spinal Curves Lumbar curve
Inward curve that develops when a child starts walking (lordotic).
After birth
Spinal Curves Deviations Kyphosis
Excessive thoracic curvature (hunchback).
Spinal Curves Deviations
Lateral curvature of the spine.
Spinal Curves Deviations
Excessive lumbar curvature (swayback).
Pectoral girdle consists of
the clavicle and scapula, supports arm movement.
Appendicular skeleton includes
includes the limbs and girdles (pectoral and pelvic).
Pelvic girdle: Composed of
the ilium, ischium, and pubis, supports lower limb movement and body weight.
Limb bones are
Humerus, radius, ulna, femur, tibia, fibula, etc. Key landmarks include condyles, epicondyles, and tuberosities for muscle attachment and articulation.
Bony differences between males and females - Pelvis
Female pelvis is wider and shallower, with a larger pelvic inlet and outlet to accommodate childbirth.
Male pelvis is narrower and more robust for support during locomotion.
Bony differences between males and females - Skull
Male skulls tend to have more prominent brow ridges, larger mastoid processes, and a squarer chin.
sutural bones are also called
Wormian
Adult skull has how may bones
22 bones (8 cranial and 14 facial).
Adult cranial bones
Frontal
parietal (2)
temporal (2)
occipital
sphenoid
ethmoid.
Adult facial bones
Maxilla (2)
zygomatic (2),
nasal (2),
lacrimal (2),
palatine (2),
inferior nasal conchae (2),
vomer,
mandible.
Sutural bones (Wormian bones) are…
Extra bones that sometimes develop in the sutures of the skull, especially in the lambdoidal suture.
Vertebral body function
Weight-bearing portion.
Spinous process function
Projects posteriorly, attachment site for muscles and ligaments.
Vertebral arch function
Forms the vertebral foramen, protecting the spinal cord
Transverse processes function
Project laterally, muscle and ligament attachment.
Articular processes function
Form joints between vertebrae (superior and inferior facets)
Intervertebral discs function
Cushioning pads between vertebrae, absorb shock and allow flexibility
vertebral column changes over a lifetime
Childhood - flexible, more cartilage
With aging, intervertebral discs lose water content and elasticity, leading to a reduction in height and potential for disc herniation
Osteoporosis can lead to vertebral compression fractures in older adults.
Pelvis formed of…
ilium, ischium, and pubis, which fuse in adulthood.
Pelvis Function
Supports the weight of the upper body, protects pelvic organs, and provides attachment points for muscles of the lower limbs.
Pelvic girdle
Also articulates with the sacrum to form the pelvic cavity.
Pelvis Sexual dimorphism
Female pelvis is adapted for childbirth, with a wider inlet, broader shape, and a more flexible pubic symphysis.
