Musculoskeletal System and Skin Flashcards
Tissue that supports, protects, and gives structure to other tissues and organs in the body. Also stores fat, helps move nutrients and other substances between tissues and organs, and helps repair damaged tissue.
i.e bone, blood, and adipose tissue and cartilage, ligaments & tendons
connective tissue
Name the type of cell that comprises cartilage and produces abundant amounts of collagen
chrondrocytes
What are the functions of cartilage?
- protects ends of bones
- resist compressive forces
- provide support on bony areas where there is a need for flexibility.
- produces collagen (via chondrocytes)
Compare and contrast a ligament vs a tendon
Tendons connect muscles with bones, and ligaments connect bones with other bones. Both are connective tissues composed of collagen
Shafts of long bones
diaphysis
heads of long bones
epiphysis
Name the type of bone
Made up of a layer of spongy bone between two thin layers of compact bone. They have a flat shape, not rounded. Examples include the skull and rib bones. They have marrow, but they do not have a bone marrow cavity.
flat bones
Include the carpal bones of the hands that allow movement of the wrist, and the tarsal bones of the feet that allow movement of the ankle. They are shaped roughly as a cube and contain mostly spongy bone. The outside surface is comprised of a thin layer of compact bone.
short bones
Bones embedded in tendons
sesamoid bones
the vertebrae, sacrum, coccyx, temporal, sphenoid, ethmoid, zygomatic, maxilla, mandible, palatine, inferior nasal concha, and hyoid.
irregular bones
a thin layer of cartilage that lies between the epiphyses and metaphyses, and is where the growth of long bones takes place.
aka the growth plate
epiphesial plate
Name the joint category
Where adjacent bones are strongly united by fibrous connective tissue. These joints allow little to know motion
fibrous joints
a type of joint where the bones are entirely joined by cartilage, either hyaline cartilage or fibrocartilage. These joints generally allow more movement than fibrous joints but less movement than synovial joints
cartilaginous joint
a type of joint which allows no movement under normal conditions i.e skull sutures, the articulations between the teeth and the mandible, and the joint found between the first pair of ribs and the sternum
synarthrosis
a joint that to binds bones together tightly while allowing a small degree of flexibility. i.e cartilaginous joint that unites the bodies of adjacent vertebrae, pubic symphis
amphiarthrosis
the matrices of bone which consist of water, collagen fibers, and crystallized minerals (These minerals serve as storage deposits for calcium and phosphate)
non-cellular structural components of bone
Name the mnenonic that can help you remember the difference between osteoblasts and osteoclasts
Osteoblasts boost BONE synthesis, while osteoclasts boost CALCIUM levels (in the blood)
Regulate local mineral deposition and chemistry at the bone matrix level, and they also function as endocrine cells producing factors that target distant organs such as the kidney to regulate phosphate transport. For the purposes of the MCAT, think of them as inactive osteoblasts
the most common type of bone cell
osteocytes
Contains blood stem cells that can become red blood cells, white blood cells, or platelets. Where hematopoiesis takes place
red bone marrow
blood cell production
hematopoiesis
aka hemapoiesis
Made mostly of fat and contains stem cells that can become cartilage, fat, or bone cells.
yellow bone marrow
What muscle types are voluntary? Involuntary?
Skeletal muscle is the only voluntary muscle type, whereas smooth and cardiac muscle are involuntary
a basic rod-like organelle of a muscle cell. Skeletal muscles are composed of long, tubular cells known as muscle fibers, and these cells contain many chains of ____. These structures are made up of actin, myosin, and other proteins
myofibrils
A structural subunit of myofibrils that are essentially repeated units of actin and myosin filaments. The contraction of this structure is responsible for muscle contractions
sarcomere
Describe the difference between the sarcoplasmic reticulum, the sarcoplasm, and the sarcolemma
These terms all correspond to structures of striated muscle cells. The sarcoplasmic reticulum is the endoplasmic reticulum, the sarcoplasm is the cytoplasm, and the sarcolemma is the cell membrane
Compare and contrast myoglobin and hemoglobin
Hemoglobin is a heterotetrameric oxygen transport protein found in red blood cells (erythrocytes), whereas myoglobin is a monomeric protein found mainly in muscle tissue where it serves as an intracellular storage site for oxygen.
Describe the relationship between T-tubules and sarcoplasmic reticulum
The function of T-TUBULES is to conduct impulses from the surface of the cell (SARCOLEMMA) down into the cell and, specifically, to another structure in the cell called the SARCOPLASMIC RETICULUM (SR). The SR stores calcium ions
Describe the characteristics of skeletal muscles
- multinucleated, meaning that a single cell contains more than one nucleus
- striated, or striped in appearance
- generally controlled voluntarily
- have red vs white fibers
Unique gap junctions found between the myocardial cells of the heart. They play vital roles in bonding cardiac muscle cells together and in transmitting signals/ions between cells.
intercalated discs
Name the 5 layers of the epidermis from top to bottom
- stratum corneum
- stratum lucidum
- stratum granulosum
- stratum spinosum
- stratum basale
Name the skin layer
Most direct physical barrier against the outside world made up of ~15 layers of dead keratinous skin cells (corneocytes). This layer sheds as it regenerates. A lipid layer surrounds the corneocytes, contributing to the skin’s impermeability to water
Stratum corneum
Name the skin layer
A clear layer of dead cells only present in the palms of the hands and the soles of the feet
stratum lucidum
Name the layer of skin
Where skin cells die and lose their nuclei after forming keratohyalin granules that link keratin filaments together into larger structures capable of serving as a hyrophobic barrier
stratum granulosum
Name the layer of skin
Also known as the prickle cell layer contains irregular, polyhedral cells with cytoplasmic processes, sometimes called “spines”, that extend outward and contact neighboring cells by desmosomes. Dendritic cells can be found in this layer. Responsible for the formation of keratinocytes.
stratum spinosum
the stratum spinosum contains Langerhans cells, which are antigen-presenting dendritic cells that help alert the immune system to pathogens invading the body via the skin
Another name for the sliding filament theory/mechanism, this process occurs when actin and myosin slide past each other, generating a **power stroke **that provides the force of a muscle contraction
The pivoting of the mysoin heads to pull the actin filaments towards the M line. As the actin is pulled toward the M line, the sarcomere shortens and the muscle contracts. When this occurs, ADP and phosphate dissociate from the myosin head.
power stroke
Fill in the (four) blanks
The ____ defines the middle of the sarcomere, running througn the middle of the thin filaments, while the ____ definees the edges, running through the middle of the thin filaments. The two bands are a way to subdivide the sarcomere. The ____ refers to the region where only thin actin filaments are present, the ____ is where only thick filaments are present and the ____ is everything else
The M-line defines the middle of the sarcomere, running througn the middle of the thin filaments, while the Z line definees the edges, running through the middle of the thin filaments. The two bands are a way to subdivide the sarcomere. The I-band refers to the region where only thin actin filaments are present, the H-zone is where only thick filaments are presentand the A-band is everything else
During a contraction, note that the sliding filament model says that the actin and myosin fibers are sliding past one another;* they are not compressed themselves*
The **A-band **is the only region that does not shrink during contractions
Fill in the blank
Actin filaments have a myosin-binding site that is blocked by the regulatory protein ____ in the absence of Ca2+
tropomyosin
both the actin and myosin filaments have structures that allow them to bind to each other when the conditions are right, and then disassociate as needed. The interplay between binding and disassociation is what drives this process along with conformational changes that take place in response to other factiors
What protein does Ca2+ bind to during muscle contractions? What is the implication of this on the myosin binding site?
Troponin. This causes tropomyosin to change its shape. This frees the myosin binding site on the relevant actin molecule. This allows the mysosin head to tightly bind to actin, forming the cross-bridge
When calcium is not present, tropomyosin is bound to actin in a position that blocks the myosin binding site. For contraction to occur, this site must be open for the head of a myosin molecule to attach.
Describe the general steps for a muscle contraction to take place, using the terms acetylcholine, calcium, T-tubule, sarcolemma, sarcoplasmic reticulum, sarcoplasm, troponin, tropomyosin, myosin, and actin
- Acetylcholine is released into neuromuscular junction
- Acetylcholine binds to sarcolemma
- Sarcolemma depolarize
- Action potential is generated and travels down T-tubules
- Action potential reaches sarcoplasmic reticulum
- Calcium is released into the sarcoplasm
- Calcium binds to troponin
- Tropomyosin changes its shape, freeing myosin site on actin
- Cross-bridge forms between actin and myosin
- ADP and phosphate dissacosiate from myosin head
- Power stroke occurs
What happens to the myosin head after the power stroke?
Myosin and actin are stuck together, until a new molecule of ATP attaches to the myosin head, causing the cross-bridge to detach
Coordinated muscle contractions are called….
Summations
When you think of summation, think of frequent action potentials being generated, disallowing the muscle fibers to fully relax, making the overall contraction become stronger
Hyperstimulation of muscle fibers causes what condition?
Tetanus
Occurs when muscles have been maximally stimulated for a period of time
