Compendium III
Chapter 11: Skeletal System
Chapter 11: Skeletal System
http://www.contmediausa.com/shop/app/products/Human3D/Images/BS000A.jpg
11.1 Overview of a Skeletal System
The skeleton supports the body, protects organs and soft parts, produces blood cells, stores minerals and fat, is utilized by muscles to produce movement.
A long bone has a shaft (diaphysis) containing a medullary cavity. Ths is lined with yellow bone marrow that stores fat. The rounded ends of the long bone are called epiphyses. These have spongy bone matter containing red bone marrow where the blood cells are made.. The outer ends of the epiphyses are covered with articular cartilage where the joints articulate.
11.1 Overview of a Skeletal System
The skeleton supports the body, protects organs and soft parts, produces blood cells, stores minerals and fat, is utilized by muscles to produce movement.
A long bone has a shaft (diaphysis) containing a medullary cavity. Ths is lined with yellow bone marrow that stores fat. The rounded ends of the long bone are called epiphyses. These have spongy bone matter containing red bone marrow where the blood cells are made.. The outer ends of the epiphyses are covered with articular cartilage where the joints articulate.
Example of Long Bone
Except for these areas, the rest of the bone is covered with a periosteum which contains blood and lymphatic vessels, and nerves. These penetrate the bone for exchange of nutrients/wastes. Compact bone is comprised of bone cells (osteocytes) arranged around the central canals which form the walls of the diaphysis. Spongy bone has a sponge-like appearance (d-uh). Thin plates (trabeculae) are separated by uneven spaces. These are also very strong and provide ample support. These are filled with red bone marrow. Cartilage has a flexible gel-like matrix and contains no nerves or blood vessels. Hyaline cartilage forms articular cartilage. Fibrocartilage is stronger and provides support in the vertebrae and knees. Elastic cartilage is as it sounds, more flexible and comprises the ear flaps and epiglottis. Ligaments and tendons are made of fibrous connective tissue. Ligaments connect bone to bone and tendons connect muscles to bones at joints.
11.2 Bone Growth, Remodeling, and Repair
Bones start to form in the fetus at six weeks when it is about ½ inch long. Bones will continue to grow or respond to stresses throughout a lifetime. Remodeling is a reaction to stresses. Bone repair is healing after a fracture.
These cells are involved in those processes:
Osteoblasts - form bone. Build the matrix and facilitate the deposit of minerals.
Osteocytes – when osteoblasts become trapped within the bone matrix, they become osteocytes which maintain the structure of the bone.
Osteoclasts - break down any extra bone framework that the osteoblasts make and help to deposit calcium and phosphate in the blood.
Ossification is the formation of bone. This occurs two ways:
Flat bones are formed from intramembranous ossification between sheets of fibous connective tissue. Long bones (most of the bones of the human skeleton) are formed by endochondral ossification. Cartilage is replaced by bone. This will continue as long as the growth plate is present. This activity will cease in women around age 18 and in men around 25 years. The diameter of a bone will grow as the bone lengthens.
Vitamin D encourages absorption of calcium in the digestive tract. Growth hormone when supported by the thyroid hormone stimulates bone growth.
Bone remodeling, or renewal, recycles as much as 18% of bone matter. This allows the body to regulate how much calcium in concentrated in our blood. Parathyroid hormone increases calcium concentrations in the blood and calcitonin has the opposite effect. Estrogen can increase osteoblasts and that is why women, whose estrogen levels are diminishing in menopause, suffer bone loss. Stress that encourages bone growth is not a bad thing, walking, strength training and jogging all encourage stronger bone growth.
Image below:
1. Hematoma forms at break 2. Fibrocartilaginous callus will fill the space 3. Bony callus formed by osteoblasts. 4. Osteoblasts build new compact bone and osteoclasts create new medullary cavity.
http://www.apatech.com/storage/images/bone2.jpg
11.3 Bones of the Axial Skeleton
The skull:
The Skull is formed by the cranium and bones of the face. These bones join together at around age 16 months. The cranium contains the sinuses which adds resonance to our voices and its airy consistency reduces the weight of the skull. The bones of the skull have the same names of the lobes of the brain. The Sphenoid bone is the keystone for all the other bones of the cranium. It extends across the floor of the cranium and up the sides.
The Facial Bones: Pictured below:
www.mc.maricopa.edu/dept/d10/asb/anthro2003/origins/webanatomy/cranium.html
The mandible is the jaw – the only part of the skull that moves.
The Hyoid Bone: The hyoid is the only bone in the body that does not interact with another bone. It is attached to the temporal bones and the larynx by ligaments and membranes. A fractured hyoid is a warning that someone
may have strangled this person.
Consists of 33 vertebrae. The normal curvature of the spinal column gives it strength. Abnormal curvatures sometimes occur. Scoliosis is a sideways curvature and Lordosis is a “swayback” or anterior curvature. There are disks between the vertebrae that absorb shock experienced from various movements. If these are compressed or bulging, they can press on the spinal nerves.
The Rib Cage: protects the heart and lungs and is flexible to allow for breathing.
The Sternum: also protects the heart and lungs.
11.4 Bones of the Appendicular Skeleton
Legs, hips and pelvis - lower part of appendicular skeleton
http://www.dmacc.edu/instructors/rbwollaston/Skeletal_System/pelvic_girdle.gif
11.5 Articulations
The joints where bones articulate. Fibrous joints don’t move. Cartilaginous joints are only slightly flexible.
Synovial (fluid-filled sacs) joints have different types of movements.
http://www.shelfieldpeonline.co.uk/assets/images/types_20of_20synovial_20joints.jpg
Chapter 12: Muscular System
12.1 Overview of muscular System
Types:
Smooth: is involuntary and internal, nonstriated, uninucleated fibers
Cardiac: is involuntary, located in heart, striated and branched
Skeletal: is voluntary, striated, tubular and is usually attached to a skeleton
http://www.nsbri.org/HumanPhysSpace/focus5/f5-190.jpg
Skeletal muscles support the body, move our bones, produce heat, assists with venous and lymph return, and protects organs. Muscles work in pairs, one contracts to move the appendage in one direction and its synergist or antagonist will move the appendage back to the original position.
http://www.etsu.edu/cpah/hsci/forsman/Histology%20of%20musclefor%20web_files/image009.jpg
The sarcopasmic reticulum contains myofibrils (contractile portions) and other organelles are located between the myofibrils. Glycogen is stored in the sarcoplasm as well as myoglobin which stores oxygen.
Sarcomeres cause striations in skeletal muscle and contain two types of protein myofilaments, thicker filaments are called myosin and the thin ones are called actin. During contraction calcium is released from the sarcoplasmic reticulum. In response, the actin slides past the myosin towards each other which shortens the muscle. This is called the sliding filament model.
Motor neurons stimulate muscles at the synaptic cleft . Neurotransmitters cross the cleft binding to receptors in the sarcolemma. The sarcolemma signals impulses over the sarcolemma and down T Tubules to the Sarcoplasmic reticulum causing contraction.
12.3 Whole Muscle Contraction
Each axon from one nerve can stimulate a number of muscle fibers. This entire group is called a motor unit. In the leg, one axon can stimulate 1000 muscle fibers, by contrast the ocular muscle group may only stimulate 23 muscle units per axon. A twitch is a short burst and a rapid series of stimuli can result in increased muscle contraction – maximum is called tetanus. When fatigue occurs, the muscle will relax even though stimuli has not.
Muscles use 4 different types of fuel sources:
Muscle triglycerides, plasma fatty acids, blood glucose, and muscle glycogen.
The creatine phosphate pathway is the quickest way to for muscles to obtain energy. This method is good for the beginning of low level exertion or 5 seconds of short-burst, high energy exertion.
The creatine is created while the muscle fibers are at rest in the midst of the sliding filaments. Only one reaction is needed to produce ATP. If the energy requirements are more than what’s available from the CP pathway, the body will utilize fermentation.
Fermentation is also fast-acting, but will result in the build-up of lactate. It is anaerobic. The process produces an oxygen debt which causes increased respirations after the exercise has ceased. The lactate will be broken down the CO2 and water (20%), and converted back into glucose and glycogen.
Cellular Respiration is used mostly when exercise is below the maximum one can expend. It uses fatty acids or glycogen stored in the muscles. This is the exercise most desirable for losing weight.
Our muscles have two types of fibers:
Fast Twitch: these are anaerobic and have more power, but fatigues easily.
Slow Twitch: are aerobic and have more endurance, good for jogging, biking or swimming.
12.4 Muscular Disorders
Spasms are intermittent involuntary muscle contractions. These can be annoying or painful. Cramps are stronger, painful spasms. Facial tics are spasms affected our faces, therefor expressions. These are involuntary, but can be controlled with difficulty.
Strains are injuries that affect muscles or tendons, thick bands that attach muscles to bones. They occur in response to a quick tear, twist, or pull of the muscle. Strains are an acute type of injury that results from overstretching or over contraction. Pain, weakness, and muscle spasms are common symptoms experienced after a strain occurs.
Sprains are injuries that affect ligaments, thick bands of cartilage that attach bone to bone. They occur in response to a stretch or tear of a ligament. Sprains are an acute type of injury that results from trauma such as a fall or outside force that displaces the surrounding joint from its normal alignment. Sprains can range from a mild ligamentous stretch to a complete tear. Bruising, swelling, instability, and painful movement are common symptoms experienced after a sprain occurs. http://physicaltherapy.about.com/od/sportsinjuries/a/strainvssprain.htm
Tendinitis is inflammation of the tendon. Bursitis is inflammation of the bursa (sac that cushions joint movements).
Myalgia is aching muscles. Fibromyalgia – a controversial chronic painful condition involving muscles. Muscular Dystrophy is an inherited condition in which there is progressive weakening of the muscles. Myasthenia Gravis is an autoimmune disease that destroys acetylcholine receptors. This is more pronounced in the head, neck, and extremities. Amyotrophic Lateral Sclerosis is also known as Lou Gehrig’s disease. Gradual loss of muscle use results in inability to chew or swallow resulting in death.
Body dysmorphic disorder – being excessively concerned and preoccupied with an imagined or minor defect in their appearance
http://farm1.static.flickr.com/144/367772579_ab90abdfd2.jpg
12.5 Homeostasis
Both muscular and skeletal systems work to maintain homeostasis.
Movement: Muscles move and are supported by skeleton
Protection: Both protect body parts
Bones are influenced by hormones to store and release calcium. Muscles need calcium for contractions.
Bones produce blood cells. Red blood cells carry oxygen needed to produce ATP by aerobic cellular respiration. White cells fight infection.
Muscles help regulate body temperature. Contracting muscles produce heat. That is why when you’re very cold, you shiver.
Except for these areas, the rest of the bone is covered with a periosteum which contains blood and lymphatic vessels, and nerves. These penetrate the bone for exchange of nutrients/wastes. Compact bone is comprised of bone cells (osteocytes) arranged around the central canals which form the walls of the diaphysis. Spongy bone has a sponge-like appearance (d-uh). Thin plates (trabeculae) are separated by uneven spaces. These are also very strong and provide ample support. These are filled with red bone marrow. Cartilage has a flexible gel-like matrix and contains no nerves or blood vessels. Hyaline cartilage forms articular cartilage. Fibrocartilage is stronger and provides support in the vertebrae and knees. Elastic cartilage is as it sounds, more flexible and comprises the ear flaps and epiglottis. Ligaments and tendons are made of fibrous connective tissue. Ligaments connect bone to bone and tendons connect muscles to bones at joints.
11.2 Bone Growth, Remodeling, and Repair
Bones start to form in the fetus at six weeks when it is about ½ inch long. Bones will continue to grow or respond to stresses throughout a lifetime. Remodeling is a reaction to stresses. Bone repair is healing after a fracture.
These cells are involved in those processes:
Osteoblasts - form bone. Build the matrix and facilitate the deposit of minerals.
Osteocytes – when osteoblasts become trapped within the bone matrix, they become osteocytes which maintain the structure of the bone.
Osteoclasts - break down any extra bone framework that the osteoblasts make and help to deposit calcium and phosphate in the blood.
Ossification is the formation of bone. This occurs two ways:
Flat bones are formed from intramembranous ossification between sheets of fibous connective tissue. Long bones (most of the bones of the human skeleton) are formed by endochondral ossification. Cartilage is replaced by bone. This will continue as long as the growth plate is present. This activity will cease in women around age 18 and in men around 25 years. The diameter of a bone will grow as the bone lengthens.
Vitamin D encourages absorption of calcium in the digestive tract. Growth hormone when supported by the thyroid hormone stimulates bone growth.
Bone remodeling, or renewal, recycles as much as 18% of bone matter. This allows the body to regulate how much calcium in concentrated in our blood. Parathyroid hormone increases calcium concentrations in the blood and calcitonin has the opposite effect. Estrogen can increase osteoblasts and that is why women, whose estrogen levels are diminishing in menopause, suffer bone loss. Stress that encourages bone growth is not a bad thing, walking, strength training and jogging all encourage stronger bone growth.
Image below:
1. Hematoma forms at break 2. Fibrocartilaginous callus will fill the space 3. Bony callus formed by osteoblasts. 4. Osteoblasts build new compact bone and osteoclasts create new medullary cavity.
http://www.apatech.com/storage/images/bone2.jpg
11.3 Bones of the Axial Skeleton
The skull:
The Skull is formed by the cranium and bones of the face. These bones join together at around age 16 months. The cranium contains the sinuses which adds resonance to our voices and its airy consistency reduces the weight of the skull. The bones of the skull have the same names of the lobes of the brain. The Sphenoid bone is the keystone for all the other bones of the cranium. It extends across the floor of the cranium and up the sides.
Axial Skeleton
The Facial Bones: Pictured below:
www.mc.maricopa.edu/dept/d10/asb/anthro2003/origins/webanatomy/cranium.html
The mandible is the jaw – the only part of the skull that moves.
The Hyoid Bone: The hyoid is the only bone in the body that does not interact with another bone. It is attached to the temporal bones and the larynx by ligaments and membranes. A fractured hyoid is a warning that someone
may have strangled this person.
Consists of 33 vertebrae. The normal curvature of the spinal column gives it strength. Abnormal curvatures sometimes occur. Scoliosis is a sideways curvature and Lordosis is a “swayback” or anterior curvature. There are disks between the vertebrae that absorb shock experienced from various movements. If these are compressed or bulging, they can press on the spinal nerves.
The Rib Cage: protects the heart and lungs and is flexible to allow for breathing.
The Sternum: also protects the heart and lungs.
11.4 Bones of the Appendicular Skeleton
Arms and shoulders - part of the appendicular skeleton
http://en.wikipedia.org/wiki/Image:Human_arm_bones_diagram.svg
http://en.wikipedia.org/wiki/Image:Human_arm_bones_diagram.svg
Legs, hips and pelvis - lower part of appendicular skeleton
http://www.dmacc.edu/instructors/rbwollaston/Skeletal_System/pelvic_girdle.gif
11.5 Articulations
The joints where bones articulate. Fibrous joints don’t move. Cartilaginous joints are only slightly flexible.
Synovial (fluid-filled sacs) joints have different types of movements.
Samples of joints:
http://www.shelfieldpeonline.co.uk/assets/images/types_20of_20synovial_20joints.jpg
Chapter 12: Muscular System
12.1 Overview of muscular System
Types:
Smooth: is involuntary and internal, nonstriated, uninucleated fibers
Cardiac: is involuntary, located in heart, striated and branched
Skeletal: is voluntary, striated, tubular and is usually attached to a skeleton
http://www.nsbri.org/HumanPhysSpace/focus5/f5-190.jpg
Skeletal muscles support the body, move our bones, produce heat, assists with venous and lymph return, and protects organs. Muscles work in pairs, one contracts to move the appendage in one direction and its synergist or antagonist will move the appendage back to the original position.
Below, is someone who does this a lot.
http://www.artlex.com/ArtLex/e/images/ecorche_contemp.chart.lg.jpg
12.2 Skeletal Muscle Fiber Contraction
Muscle fibers are cells that have similar cellular componants to other cells, but they have been given specific names. The plasma membrane is sarcolemma, cytoplasm is sarcoplasm, endoplasmic reticulum is sarcoplasmic reticulum.
http://www.artlex.com/ArtLex/e/images/ecorche_contemp.chart.lg.jpg
12.2 Skeletal Muscle Fiber Contraction
Muscle fibers are cells that have similar cellular componants to other cells, but they have been given specific names. The plasma membrane is sarcolemma, cytoplasm is sarcoplasm, endoplasmic reticulum is sarcoplasmic reticulum.
Anatomy of muscle and how it is attached to the bone
http://www.sci.sdsu.edu/class/bio590/pictures/lect1/structureofskelmus1.jpeg
http://www.sci.sdsu.edu/class/bio590/pictures/lect1/structureofskelmus1.jpeg
More anatomy of muscle:
http://www.etsu.edu/cpah/hsci/forsman/Histology%20of%20musclefor%20web_files/image009.jpg
The sarcopasmic reticulum contains myofibrils (contractile portions) and other organelles are located between the myofibrils. Glycogen is stored in the sarcoplasm as well as myoglobin which stores oxygen.
Sarcomeres cause striations in skeletal muscle and contain two types of protein myofilaments, thicker filaments are called myosin and the thin ones are called actin. During contraction calcium is released from the sarcoplasmic reticulum. In response, the actin slides past the myosin towards each other which shortens the muscle. This is called the sliding filament model.
Motor neurons stimulate muscles at the synaptic cleft . Neurotransmitters cross the cleft binding to receptors in the sarcolemma. The sarcolemma signals impulses over the sarcolemma and down T Tubules to the Sarcoplasmic reticulum causing contraction.
12.3 Whole Muscle Contraction
Each axon from one nerve can stimulate a number of muscle fibers. This entire group is called a motor unit. In the leg, one axon can stimulate 1000 muscle fibers, by contrast the ocular muscle group may only stimulate 23 muscle units per axon. A twitch is a short burst and a rapid series of stimuli can result in increased muscle contraction – maximum is called tetanus. When fatigue occurs, the muscle will relax even though stimuli has not.
Muscles use 4 different types of fuel sources:
Muscle triglycerides, plasma fatty acids, blood glucose, and muscle glycogen.
The creatine phosphate pathway is the quickest way to for muscles to obtain energy. This method is good for the beginning of low level exertion or 5 seconds of short-burst, high energy exertion.
The creatine is created while the muscle fibers are at rest in the midst of the sliding filaments. Only one reaction is needed to produce ATP. If the energy requirements are more than what’s available from the CP pathway, the body will utilize fermentation.
Fermentation is also fast-acting, but will result in the build-up of lactate. It is anaerobic. The process produces an oxygen debt which causes increased respirations after the exercise has ceased. The lactate will be broken down the CO2 and water (20%), and converted back into glucose and glycogen.
Cellular Respiration is used mostly when exercise is below the maximum one can expend. It uses fatty acids or glycogen stored in the muscles. This is the exercise most desirable for losing weight.
Our muscles have two types of fibers:
Fast Twitch: these are anaerobic and have more power, but fatigues easily.
Slow Twitch: are aerobic and have more endurance, good for jogging, biking or swimming.
12.4 Muscular Disorders
Spasms are intermittent involuntary muscle contractions. These can be annoying or painful. Cramps are stronger, painful spasms. Facial tics are spasms affected our faces, therefor expressions. These are involuntary, but can be controlled with difficulty.
Strains are injuries that affect muscles or tendons, thick bands that attach muscles to bones. They occur in response to a quick tear, twist, or pull of the muscle. Strains are an acute type of injury that results from overstretching or over contraction. Pain, weakness, and muscle spasms are common symptoms experienced after a strain occurs.
Sprains are injuries that affect ligaments, thick bands of cartilage that attach bone to bone. They occur in response to a stretch or tear of a ligament. Sprains are an acute type of injury that results from trauma such as a fall or outside force that displaces the surrounding joint from its normal alignment. Sprains can range from a mild ligamentous stretch to a complete tear. Bruising, swelling, instability, and painful movement are common symptoms experienced after a sprain occurs. http://physicaltherapy.about.com/od/sportsinjuries/a/strainvssprain.htm
Tendinitis is inflammation of the tendon. Bursitis is inflammation of the bursa (sac that cushions joint movements).
Myalgia is aching muscles. Fibromyalgia – a controversial chronic painful condition involving muscles. Muscular Dystrophy is an inherited condition in which there is progressive weakening of the muscles. Myasthenia Gravis is an autoimmune disease that destroys acetylcholine receptors. This is more pronounced in the head, neck, and extremities. Amyotrophic Lateral Sclerosis is also known as Lou Gehrig’s disease. Gradual loss of muscle use results in inability to chew or swallow resulting in death.
Body dysmorphic disorder – being excessively concerned and preoccupied with an imagined or minor defect in their appearance
http://farm1.static.flickr.com/144/367772579_ab90abdfd2.jpg
12.5 Homeostasis
Both muscular and skeletal systems work to maintain homeostasis.
Movement: Muscles move and are supported by skeleton
Protection: Both protect body parts
Bones are influenced by hormones to store and release calcium. Muscles need calcium for contractions.
Bones produce blood cells. Red blood cells carry oxygen needed to produce ATP by aerobic cellular respiration. White cells fight infection.
Muscles help regulate body temperature. Contracting muscles produce heat. That is why when you’re very cold, you shiver.
skyview.billings.k12.mt.us/.../shivering.gif
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