anatomy fall midterm
A certain protein found at the epiphyseal plate inhibits the activity of osteoblasts (this is the normal, healthy condition). What would happen if this protein were faulty and could not restrict osteoblast activity? A.The affected individual would have a thinner mandible B.The affected individual would have longer adult femurs C.The affected individual would have shorter adult femurs D.The affected individual would have a thinner mandible
C.The affected individual would have shorter adult femurs
When comparing anatomical regions, ______ is proximal to ______. A.cranial; pedal B.palmar; brachial C.popliteal; gluteal D.patellar; pedal
D. patellar; pedal
2 layers of perisoteum
Fibrous outer: dense irregular CT Cellular inner: osteoblasts, osteoclasts & osteoprogenitor cells
how does a nucleic acid make a protein?
Read code & assemble of amino acid string = translation mRNA read by ribosomes tRNA brings proper amino acid from cytoplasm to ribosome Ribosomes assemble protein strings
maintains itself and replaces mineral reserves
adult skeleton
where do trabeculae and osteons orient?
along lines of stress
fixed ribosomes
attached to ER
what happens to heavily stressed bones?
become thicker and stronger
calcified (made rigid by calcium salts, minerals) for weight support
bone
the skeletal system includes
bones, cartilage, ligaments and connective tissues
extrinsic control
brain/nervous system/endocrine system (systematic)
osteoblasts
build
The process of depositing calcium salts Occurs during bone ossification and in other tissues
calcification
osteoprogenitor cells
can become blasts
what does the nucleus contain?
chromatin and chromosomes made of DNA
moves fluids across the cell surface core is made of microtubules
cilia
The condition Marfan syndrome is a genetic disorder that affects proper production of the extra-cellular matrix protein fibrillin-1. Fibrillin-1 is necessary for proper production of elastic tissue fibers in the extracellular matrix, though other matrix fibers of these tissues are not affected. When elastic fibers are not properly formed, certain organs are severely affected. In extreme cases, the most affected organs include the large blood vessels near the heart which become weak, inelastic and can tear open (this is very bad and can cause immediate death). For Marfan syndrome, the tissue in blood vessels that is affected is most likely: Muscle Epithelial Connective Nervous
connective
what will bones do without collagen?
crumble (collagen makes bones flexible)
all materials inside the cell and outside the nucleus
cytoplasm
attachment and stabilization tightly packed, parallel collagen fibers (tendons and ligaments)
dense connective tissue
along bone surface
depressions or grooves
osteoclasts
destroy
in the ear and epiglottis
elastic cartilage
specialized cells of connective tissues
fibroblasts/ fibrocytes blood cells adipocytes osteocytes chondrocytes
move cell
flagella
allow flow of nutrients through diffusion from inner cells to outer most osteocytes on the osteon cellular connections
gap junctions
cartilage
gel-type ground substance for shock absorption and protection
repacking transport vesicles lysosomes
golgi apparatus
rough ER
has ribosomes attached
maintaining a stable internal environment
homeostasis
Embryonic skeleton, surfaces of synovial joints, etc.
hyaline cartilage
free ribosomes
in cytoplasm
appositional growth
increase size by adding to outer surface
old osteons that are partially remodeled
interstitial lamellae
what are 2 ways that bones form?
intramembranous and endochondral
replaces mesenchyme tissue with bone
intramembranous ossification
concentric rings of collagen laid down in different angles in subsequent stronger and allows for resisting of twisting force from any direction
lamellae
skeletal muscle tissue
large body muscles responsible for movement
connect bone to bone and stabilize organs
ligaments
chromatin
loosely coiled DNA (cells not dividing)
spongy bone anatomy
macroscopic trabeculae bone marrow between trabeculae microscopic irregular lamellae of matrix and osteocytes connected by canaliculi
majority of tissue volume protein fibers ground substance fills spaces between cells varied composition
matrix (extracellular components)
sex cell nuclear division exact copy but 4 daughter cells made different
meiosis
where are all connective tissues derived from?
mesenchymal cells
where diaphysis and epiphysis meet
metaphysis
somatic cell nuclear division exact copy of DNA made and 2 daughters produced Identical
mitosis
long bone structure: epiphysis
mostly spongy covered with compact bone
2 types of neural cells
neuron - nerve cells neuroglia- support cells
Your heart rate (the rate at which it pumps blood) varies depending on your degree of physical activity or neural/hormonal activity. With exercise or fear, heart rate increases to pump more blood to an active body. Yet after exercise, heart rate decreases to a resting level. There are several nerves and hormones that stimulate heart rate to increase as needed, or decrease when needed, but there is no receptor that monitors heart rate. Is heart rate homeostatically regulated?
no
smooth ER
no attached ribosomes
cell's control center contains the code (DNA) for protein structures of cell and therefore functions of the cell
nucleus
structures with specific functions
organelles
biomolecules
organic compounds
diffusion of a solvent such as water through a specific channel protein or through the lipid bilayer
osmosis
the process of replacing other tissues with bone
ossification
mature bone cell that maintains the bone matrix live in lacunae are between layers (lamellae) of matrix connect by canaliculi in lamellae to access blood supply do not divide maintain protein and mineral content of matrix help repair damaged bone
osteocyte
bone ct is made of
osteocytes- osteoblasts, osteoclasts, osteoprogenitor (only 2%) matrix-collagen fibers (1/3), calcium salts (2/3)
double layer of phospholipid molecules
phospholipid bilayer
intensifies a change in the body's physiological condition rather than reversing it
positive feedback
homeostatic regulation requires:
receptor, control center, effector
recycles and renews bone matrix involves osteocytes, osteoblasts, & osteoclasts
remodeling
build proteins
ribosomes
2 types of transport vesicles
secretory and membrane
physiological value around which the normal range fluctuates
set point
muscle tissue
specialized for contraction produces all body movements 3 types
protects against attacks keratin proteins add strength and water resistance
stratified squamous epithelium
Functions of the skeletal system
support protection storage of minerals (calcium) storage of lipids (yellow marrow) blood cell production (red marrow) movement
attach muscles to bones
tendons
where and when does endochondral ossification take place
throughout adolescence at growth plates
chromosomes
tightly coiled DNA (cells dividing)
True or False? Blood calcium is homeostatically regulated by the endocrine system.
true
true or false? Membrane transport using a protein can be passive or active.
true
cancer
unregulated cell growth and division
uses a vesicle for transport and always active
vesicular transport
The medulla of the kidney contains a very salty extracellular fluid. Consequently, water in the cells of the kidney: A.diffuses out of the cells into the extracellular fluid. B.is pumped out of the cells into the extracellular fluid. C.diffuses into the cells out of the extracellular fluid. D.is pumped into the cells out of the extracellular fluid.
A.diffuses out of the cells into the extracellular fluid.
Bone tissue (or osseous tissue) is composed of extracellular collagen (a large protein), mineral (calcium salts and other minerals) and bone cells (i.e. osteocytes). Osteogenesis Imperfecta (OI, aka brittle bone disease) is a congenital bone disorder in which a mutation in the DNA results in a change in one monomer of collagen. Improper formation of collagen fibers leads to an irregular arrangement of osseous tissue. This results in brittle, easily broken bones. For OI, what type of monomer is affected in the collagen fibers? Amino acid Monosaccharide Glycerol Nucleotide
Amino acid
Which bony structures remodel most rapidly in response to changing pressures on the bone?A.Osteons B.Canaliculi C.Trabeculae D.Yellow bone marrow
C.Trabeculae
examples of vesicular transport
Exocytosis, Phagocytosis, Pinocytosis, endocytosis
True or False? Flagella are used to move fluids across the surface of the cell.
False False indeed. Cilia are used to move fluids across the surface of their cells. Cells with cilia are anchored in place but may need to propel the fluid around them. Flagella allow a cell to move through its liquid environment. Sperm are the only flagellated cells in the human body.
Long Bone Structure: Diaphysis
heavy wall (cortex) of compact bone a central space called marrow cavity
true or false? Negative feedback loops help maintain equilibrium conditions.
true
true or false?Osteoprogenitor cells differentiate to form osteoblasts which mature into osteocytes.
true
For Neuron Signaling, if blood Ca2+ is homeostatic regulated, this means: A.there are receptors for blood Ca2+. B.it is important to neuron signaling . C.is controlled by the nervous system. D.it is an organic molecule.
A.there are receptors for blood Ca2+.
energy form for cells made on demand in cytoplasm by enzymes or in mitochondria cannot be stored or transferred between cells
ATP (adenosine triphosphate)
The epithelia of your esophagus must protect against abrasion but do not aid in the absorption of nutrients or secretion of digestive enzymes. What epithelial tissue type would you expect to find in the esophagus? A.Simple columnar epithelium B.Stratified squamous epithelium C.Simple cuboidal epithelium D.Stratified columnar epithelium
B.Stratified squamous epithelium
Which represents the same level of organization as endosteum? A.Calcium B.Trabeculae C.Collagen D.Femur
B.Trabeculae
Which process occurs in the nucleus when DNA is organized as chromatin?A.Mitosis B.Transcription C.Translation D.Meiosis
B.Transcription
True or False? Meiosis produces gametes that are genetically identical to the parent cell and are used in reproduction.
False Yes! Although it is true that meiosis produces sex cells for reproduction, the gametes that are produced are not genetically identical to the parent cells. Instead, they contain half the DNA of the parent cell.
What is the difference between spongy and compact bone? Spongy bone and compact bone are microscopically arranged differently Spongy bone and compact bone are not both found in long bones Spongy bone and compact bone contain different cellular populations Spongy bone and compact bone are made of different matrix material
Spongy bone and compact bone are microscopically arranged differently Right! Spongy bone and compact bone are made of the same matrix material (1/3rd collagen, 2/3rds mineral), contain the same cellular populations (osteoblasts, osteoclasts, osteocytes, osteoprogenitor cells) and are both found in long bones. Microscopically, the matrix arranges itself as osteons in compact bone, but as non-osteon, irregular lamellae of trabeculae in spongy bone.
In which of the following would you expect to find osteons? The diaphyseal cortex of the humerus The ligaments connecting adjacent vertebrae The medullary (marrow) cavity of the femur The epithelium of the oral cavity The trabeculae of the humeral distal epiphysis
The diaphyseal cortex of the humerus Right! Osteons are the structural unit of compact bone. They make up the thick walls of long bone diaphyses and the most superficial compact bone (cortex) of long bone epiphyses. Compact bone is found in all bones with variable amounts of spongy bone between compact bone regions. Osteons do not exist in the ligaments of the vertebral column (a dense regular connective tissue) or in epithelia. The medullary (marrow) cavities of long bones contain bone marrow (red or yellow, more likely yellow). Perhaps you selected the trabeculae within an epiphysis. Trabeculae are spongy bone struts. While spongy bone is made of the same material as compact bone, the organization is different and osteons do not form. It is important to remember the terms epiphysis and diaphysis - we will use them more when we talk about how bone grows.
In an infant's humerus, what happens if the rate of hyaline cartilage death is faster than the rate of interstitial growth? Nothing - this would not affect humerus development. The humerus would become too short at full maturity. The humerus would become too long at full maturity.
The humerus would become too short at full maturity. Right! The humerus is a long bone that grows through endochondral bone formation. During endochondral bone formation hyaline cartilage grows on one aspect of the epiphyseal plate (epiphyseal side) as it dies on the other (diaphyseal side). As it dies, it is degraded and replaced by bone. If the rate of growth is slower than the rate of death and replacement, the bone will replace the existing cartilage completely. Because bone is a hard tissue, it cannot grow from within (interstitial growth) to further elongate the bone and thus a long bone cannot grow any longer once the cartilage at the plate is gone. Too fast cartilage death is a problem in certain forms of dwarfism that results in smaller stature.
True or False? Endochondral bone formation stops at birth.
false
_____ are useful in the skeleton because they remodel most readily in response to stress and efficiently transmit forces while remaining lightweight. trabeculae osteons articular cartilages cortical bone adjacent to periosteum
trabeculae Right! Trabeculae are the struts of spongy bone in the epiphyses and adjacent to the medullary cavity. They are more lightweight than dense compact bone (as evidenced by their many open spaces). In the epiphyses they transmit weight to the more dense compact bone of the diaphyseal cortex. They remodel very rapidly in response to signals (compressive stress/hormonal fluctuations); the proximal femoral spongy bone remodels every 3-6 months but the denser compact bone may take 3-7 years to fully remodel. Osteons are the structural unit of compact bone; compact bone comprises the bulk of the diaphyseal cortex (cortical bone) and the part adjacent to the periosteum. Articular cartilages (cartilage on the end of long bones) do not function for weight bearing as much as they function for friction reduction. They do not remodel in response to stress like spongy bone trabeculae do.
where blood and nerves enter bone
tunnels
what would happen if a distance runner became a body builder?
will have increase in differentiation of osteoprogenitor to osteoblasts to deal with increased stress from heavy weights
For Neuron Signaling, how does Ca2+ exit neurons?A.Via exocytosis B.Via simple diffusion C.Via facilitated diffusion D.Via active transport
D.Via active transport
instructions for every protein in the body
DNA
Oxygen is essential for cellular respiration and therefore must cross the cell membrane. Which of the following would increase O2 transport into a cell? Increasing surface area of the cell's membrane Increasing the concentration of O2 inside of the cell Increasing the number of membrane transport proteins for O2
Increasing surface area of the cell's membrane
what allows bones to adapt to stress?
Mineral recycling
outer lamellae around whole cortex deposited by cells on the inside of the periosteum
circumferential lamellae
Structural proteins for shape and strength (keratin) Internal scaffolding, anchor other organelles Act as "zip lines" for organelle, molecule transport Cell contraction: actin & myosin
cytoskeleton
intracellular fluid
cytosol
where tendons and ligaments attach at articulations with other bones
elevations/projections
replacing avascular cartilaginous model with a highly vascular bony model
endochondral
synthesis of proteins, carbs and lipids storage of synthesized molecules and materials transport of materials within detoxification of drugs or toxins
endoplasmic reticulum
Intervertebral disks, pads within knee joint & pubic symphysis
fibrocartilage
DNA instructions for 1 protein
gene
What are biomolecules?
hydrogen, oxgen, nitrogen, and phosphorus
a mechanism that reverses a deviation from the set point, and in turn, maintains body parameters within their normal range
negative feedback loop
Immature bone cells that secrete matrix compounds (osteogenesis) Osteoid is the matrix produced, but not yet calcified trapped by matrix become osteocytes
osteoblasts
Giant, multinucleate cells Secrete acids and protein-digesting enzymes Dissolve bone matrix and release stored minerals (osteolysis) Are derived from stem cells that produce macrophages
osteoclasts
Arrange the following structures in the correct order starting with the simplest level of organization and ending with the most complex. 1. Cell membrane 2. Epithelial cell 3. Human 4. Digestive system 5. Phospholipid 6. Small intestine
5, 1, 2, 6, 4, 3
Arrange the following in the correct order for the development of a clavicle. 1. Osteoid calcifies 2. Trabeculae merge and become surrounded by blood vessels 3. Osteoblasts differentiate from stem cells 4. Cortical bone develop around the edges A.3, 4, 1, 2 B.3, 1, 2, 4 C.2, 3, 1, 4 D.2, 4, 3, 1
B.3, 1, 2, 4
Keratin is an intracellular protein. How is it made? By a free ribosome In the rough ER In the smooth ER In the nucleus
By a free ribosome Free ribosomes synthesize proteins for intracellular purposes. Fixed ribosomes on the rough ER synthesize proteins as well, but those are exported from the cell to be used on the cell membrane or elsewhere in the body. The nucleus contains the genetic code in the form of DNA to determine the structure of proteins. The smooth ER makes carbohydrates and lipids.
Which tissue type is charaterized by cells scattered throughout an extracellular matrix of proteins? Muscle Epithelial Connective Nervous
Connective That's right! Connective tissue is made up of relatively few cells (as opposed to epithelial and muscle tissue) scattered throughout an extracellular matrix. Many seemingly disparate tissues in the body are connective: bone, blood, and dense connective tissue (tendons) to name a few. You may have noticed that these details about tissue types are not included in the slides I posted for you. Remember, posted slides are only an outline. It is up to you to complete them by listening in lecture and supplementing the outline.
A cell without ______ cannot ______. A.microvilli; absorb molecules B.mitochondria; produce ATP C.cilia; move D.ribosomes; produce proteins
D.ribosomes; produce proteins
Bone tissue (or osseous tissue) is composed of extracellular collagen (a large protein), mineral (calcium salts and other minerals) and bone cells (i.e. osteocytes). Osteogenesis Imperfecta (OI, aka brittle bone disease) is a congenital bone disorder in which a mutation in the DNA results in a change in one monomer of collagen. Improper formation of collagen fibers leads to an irregular arrangement of osseous tissue. This results in brittle, easily broken bones. To help treat OI, patients are prescribed dietary supplements with high concentrations of vitamin D, a fat-soluble vitamin. How will the vitamin D cross into the cells lining the GI tract to be absorbed into the body? Using a transport protein Osmosis Directly through the phospolipid bilayer Hydrolysis
Directly through the phospolipid bilayer
Mature osseous connective tissue (bone) is composed of collagen fibers and mineralized matrix. When osseous CT is first made, the osteoblasts secrete osteoid onto which calcium salt then precipitates. What is osteoid? Hyaline cartilage Mostly collagen or collagen pre-cursors Mesenchyme
Mostly collagen or collagen pre-cursors Right! Osteoid is the immature bone that is first formed. It contains the collagen fibers and proteins that promote calcium salt formation onto the collagen. Hyaline cartilage is a different connective tissue that makes embryonic protoskeletons and articular cartilage. Mesenchyme is an embryonic connective tissue made of mesenchymal cells in a liquid ground substance.
Mesenchymal stem cells that divide to produce osteoblasts Located in inner, cellular layer of periosteum and in endosteum Important in fracture repair
Osteoprogenitor (Osteogenic) Cells
Tendons, which are composed of connective tissue, have many collagen fibers. Which of the following best describes where these fibers are located? In the ground substance that is within the fibroblasts Outside the fibroblasts, in the extracellular matrix In the ground substance that is within the chondrocytes Outside the chondrocytes, in the extracellular matrix
Outside the fibroblasts, in the extracellular matrix The fibers of connective tissues are part of the extracellular matrix (outside the cells). Ground substance refers to the non-fiber part of the extracellular matrix. Fibroblasts are the cell type found in tendons (dense regular connective tissues) and they are responsible for producing the collagen fibers. Chondrocytes are cartilage cells and are not found in tendons, they are found in cartilaginous structures like the ends of bones, intervertebral discs and knee menisci.
What is its role of endosteum in bone? The endosteum has collagen fibers that anchor attaching muscles. The endosteum can add or remove cartilage from the inside of bones, replacing bone with cartilage. The endosteum is an epithelial layer that protects the inside of bones and regulates transportation of nutrients to bones. The endosteum can add or remove bone from the inside of bones, remodeling them.
The endosteum can add or remove bone from the inside of bones, remodeling them. Right! The endosteum is made of connective tissue cells (not epithelial cells) that can deposit or reabsorb bone from the internal aspect of the bone. During growth, the endosteum is particularly important to remodel bone from the inside. Without endosteal bone reabsorption, as bones grow wider overall, the bone would become too heavy. In other words, as bones grow wider (due to periosteal bone deposition), they maintain the same cortical bone thickness because of endosteal removal. Cartilage is deposited by chondroblasts. Muscles attach at the outside of bone on the fibrous layer of the periosteum.
When you swim in a pool, your body gains water. When you swim in the ocean you lose water. What most likely explains these observations? The pool water is more salty than the inside of your body (and cells); the ocean water is less salty than the inside of your body (and cells) The pool water is less salty than the inside of your body (and cells); the ocean water is also less salty than the inside of your body (and cells) The pool water is more salty than the inside of your body (and cells); the ocean water is also saltier than the inside of your body (and cells) The pool water is less salty than the inside of your body (and cells); the ocean water is saltier than the inside of your body (and cells)
The pool water is less salty than the inside of your body (and cells); the ocean water is saltier than the inside of your body (and cells) Correct! Water moves passively (does not require cellular energy to move) to a place where there is less water (relatively). When we say less water, it is not in absolute terms, but instead we are talking about concentrations. If a liquid has lots of salt and little water, we say that solution is very concentrated in salt but it has relatively little water. If another solution has little salt (or other dissolved substance, like sugar) we say it is dilute and has relatively much water. A swimming pool is very dilute and compared to the inside of your body, it has fewer dissolved particles for each molecule of water. Therefore water moves away from where there is more water (in the pool) to where there is less (your body) - water enters your body and makes your body swollen. The ocean is very salty - it has many dissolved salt particles for each molecule of water. When you swim in the ocean, you lose water to the ocean because the leaving water is trying to "dilute" the ocean's salt. This process is osmosis and it occurs across every body cell. In response to wet conditions, you skin wrinkles. Interestingly, this is due to neural activation - if the nerves are cut, you skin does not wrinkle (or prune) despite the presence of external water. It is believed this response increases finger grip in wet conditions.
Glucose and oxygen are used to produce energy for muscle action - this process occurs within each cell. Your new workout partner tells you that the supplement he's taking allows him to produce more energy because it increases oxygen delivery by increasing the number of cell membrane protein carriers for oxygen. What would you say to him? That sounds great - can I have some? Yes, the number of oxygen molecules that can enter a cell is directly related to the number of oxygen transport proteins on the cell membrane. This seems unlikely because oxygen does not require membrane proteins for transport across the cell membrane. No answer text provided.
This seems unlikely because oxygen does not require membrane proteins for transport across the cell membrane. Correct! Oxygen is fat soluble and moves through the cell membrane unassisted. Only substances that cannot dissolve in the cell membrane require membrane proteins (channels or carriers) to cross the membrane. Such substances include charged ions (sodium, potassium, calcium) and molecules like glucose and amino acids. However, if a supplement increased the number of glucose transport proteins in a cell membrane, it would increase the number of glucose molecules that enter a cell. In our bodies, cells frequently change the number of transporters or receptors for specific molecules to increase transport in/out of a cell or the likelihood of reaction a cell has to a substance.
Which of the following make up spongy bone? Trabeculae Osteons Cortical bone Articular cartilage
Trabeculae Right! Trabeculae are the struts of spongy bone in the epiphyses and adjacent to the medullary cavity. They are more lightweight than dense compact bone (as evidenced by their many open spaces). In the epiphyses they transmit weight to the more dense compact bone of the diaphyseal cortex. They remodel very rapidly in response to signals (compressive stress/hormonal fluctuations); the proximal femoral spongy bone remodels every 3-6 months but the denser compact bone may take 3-7 years to fully remodel. Osteons are the structural unit of compact bone; compact bone comprises the bulk of the diaphyseal cortex (cortical bone) and the part adjacent to the periosteum (outer connective tissue layer used for bone remodeling and muscle/ligament attachment). Articular cartilages (cartilage on the end of long bones) do not function for weight bearing as much as they function for friction reduction. They do not remodel in response to stress like spongy bone trabeculae do.
In vitamin C deficiency you cannot synthesize collagen. Which of the following would most likely occur? You would not be able to replenish lost epithelial cells. Your cartilage would become avascular. Your skeleton would become malformed. You would not be able to sweat.
Your skeleton would become malformed. Right! The skeleton is constantly being degraded and replaced. Since the skeleton is 1/3rd collagen and 2/3rds mineral, an inability to make collagen would substantially affect the skeleton. Furthermore, proper collagen formation is required for proper bone mineral deposition. Epithelial cells do not have collagen. Sweat is mostly water and salt, and should not have collagen. Sweat glands are made of epithelial tissue, not lots of collagen like you would find in tendons/ligaments or bone. Cartilage is already avascular and actually secretes a compound that inhibits blood vessel formation. The best answer here is the one discussing skeleton formation.
In vitamin C deficiency you cannot synthesize collagen. Which of the following would most likely occur? Your skeleton would become malformed. You would not be able to replenish lost epithelial cells. You would not be able to sweat. Your cartilage would become avascular.
Your skeleton would become malformed. The skeleton is constantly being degraded and replaced. Since the skeleton is 1/3rd collagen and 2/3rds mineral, an inability to make collagen would substantially affect the skeleton. Furthermore, proper collagen formation is required for proper bone mineral deposition. Epithelial cells do not have collagen. Sweat is mostly water and salt, and should not have collagen. Sweat glands are made of epithelial tissue, not lots of collagen like you would find in tendons/ligaments or bone. Cartilage is already avascular and actually secretes a compound that inhibits blood vessel formation. The best answer here is the one discussing skeleton formation.
enzymes: store the genetic information of each cell. are the preferred energy source of most body cells. are denatured in the process of catalysing reactions. act on substrates that fit their active site.
act on substrates that fit their active site.
neural tissue
carries electrical signals from 1 part of the body to another rapidly senses internal or external environment process info and controls responses neural tissue is concentrated in the central nervous system
make extra organelles, copy DNA, divide it all up
cell division
characteristics of epithelia
cellularity (cell junctions) polarity (apical and basal surfaces) attachment (basement membrane) avascularity regeneration
compact bone microanatomy: osteon
concentric lamellae of matrix central canal contains blood vessels, nerves osteocytes connected by canaliculi
what do DNA proteins do?
determine cell structure and function because enzymes & cell parts are made of proteins
Lysosomes
digestive enzymes
2 monomers joined through dehydration synthesis
dimer
Covers all internal surfaces of cavities within bones Medullary cavity Trabeculae Central canal of osteon Single layer of: osteoblasts, osteoclasts & osteogenic cells
endosteum
site of post natal long bone elongation cartilage replaced by bone in growing skeleton
epiphyseal plate
layers of cells covering internal or external surfaces protection and permeability
epithelia
interstitial growth
expands from within
connective tissue
fills internal spaces supports other tissues transports materials stores energy protects/insulates isolates mesenchyme
smooth muscle tissue
found in walls of hollow, contracting organs
cardiac muscle tissue
found only in the heart
what does DNA store?
genetic instructions for making proteins
structures that produce secretions
glands
3 types of cartilage
hyaline, elastic, fibrocartilage
outfoldings of plasma membrane increased surface area for absorption found in small intestine
microvilli
provides cells with energy for life require oxygen and organic substrates generate carbon dioxide and ATP
mitochondria
bone formation
osteogenesis
collagen fiber (mainly) and some proteins that allow calcium to condense Indicates new bone formation In all individuals of all ages
osteoid
what cells are derived from mesenchymal cells
osteoprogenitor fibroblasts chondroprogenitor bone marrow cells
Which is the lowest level of organization? (lowest of the options) oxygen mitochondria muscle fiber biceps brachii
oxygen
Covers all bones (except at articular surfaces) 2 layers Ligaments/tendons merge Sharpey's fibers
periosteum
surrounds bones some connective tissue for muscle attachment inner layer is full of osteocytes
periosteum
where does appositional growth happen? what happens?
periosteum become circumferential lamellae or osteons form around blood vessels osteoclasts enlarge marrow cavity
fat-soluble molecules directly through the phospholipid bilayer
simple diffusion
thin barrier allows diffusion
simple squamous epithelium
three types of muscle tissue
skeletal cardiac smooth
how is DNA code read?
specific sequence for specific amino acids--> proteins enzyme in nucleus reads sequence and makes complimentary mRNA = transcription
metastasis
spread of cancer cells to different locations
supportive connective tissue
support soft tissues and body weight (cartilage)
homeostatic regulation
systems respond to changes to function within a normal range physiological systems work to restore balance
For Neuron Signaling, which of the following would cross the membrane in the same way as neurotransmitter. A.Alcohol B.Collagen C.Na+ D.O2
B.Collagen
Which tissue type is commonly found binding organs together and contains cells that are widely spaced? A.Nervous B.Connective C.Muscle D.Epithelial
B.Connective
Which are best described as membranous extensions that promote absorption into a cell? A.Lysosomes B.Microvilli C.Cilia D.Cytoskeleton
B.Microvilli
In endochondral ossification: A.spongy bone forms before compact bone B.mesenchyme is replaced by osteoid. C.blood vessels deliver osteoblasts. D.bone forms first in the epiphyses
C.blood vessels deliver osteoblasts.
For Neuron Signaling, depending on the type of membrane protein it binds to, a neurotransmitter can have either excitatory or inhibitory effects. This is an example of: A.cellular structure affecting molecular structure. B.molecular function affecting cellular structure. C.molecular structure affecting cellular function. D.cellular function affecting molecular structure.
C.molecular structure affecting cellular function.
For Neuron Signaling, where would you find cells with all of the same DNA as found in neurons? A.In all nervous tissue cells, but not in other body cells B.In all somatic cells and gametes C.In neurons only D.In all somatic cells of the body
D.In all somatic cells of the body
For Neuron Signaling, some neurotransmitters are amino acid based. What organelles would you expect to be found in neurons for the production of these neurotransmitters? A.Free ribosomes, nucleus and mitochondria B.Smooth ER, golgi and lysosomes C.Mitochondria, cytoskeleton, and cilia D.Rough ER, golgi and nucleus
D.Rough ER, golgi and nucleus
True or False? Chemical messengers depend on their three-dimensional shapes to bind with cellular receptors. If the structure of the messenger is altered, it will still be able to bind with the cellular receptor.
False False indeed. If a structure is altered, its function will likely be affected as strucutre dictates function.
True or False? Small, fat-soluble molecules require transport proteins to cross the cell membrane.
False Yes! Generally speaking, small uncharged molecules, gasses and fat-soluble molecules can pass through the cell membrane without a channel, carrier or transport protein, as long as they are traveling DOWN their concentration gradient. Ions and larger water soluble molecules require protein channels, carriers or transport proteins to cross the membrane.
autoregulation
comes from within
The condition Marfan syndrome is a genetic disorder that affects proper production of the extra-cellular matrix protein fibrillin-1. Fibrillin-1 is necessary for proper production of elastic tissue fibers in the extracellular matrix, though other matrix fibers of these tissues are not affected. When elastic fibers are not properly formed, certain organs are severely affected. In extreme cases, the most affected organs include the large blood vessels near the heart which become weak, inelastic and can tear open (this is very bad and can cause immediate death). True or False. For Marfan syndrome, the cells that produce fibrillin-1 divide using meiosis in a growing individual. True False
false
True or False? Bone mass must be maintained to ensure sufficient structural support. Certain bone cells can build and break down bone in response to hormonal changes, but there is no receptor for bone mass. Bone mass is homeostatically regulated.
false
true or false? Bones like the femur are only composed of connective tissue.
false
true or false? Hydrophobic tails of phospholipids allow the diffusion of carbohydrates into and out of cells.
false
true or false? The periosteum is a protective epithelial covering on bones
false
The condition Marfan syndrome is a genetic disorder that affects proper production of the extra-cellular matrix protein fibrillin-1. Fibrillin-1 is necessary for proper production of elastic tissue fibers in the extracellular matrix, though other matrix fibers of these tissues are not affected. When elastic fibers are not properly formed, certain organs are severely affected. In extreme cases, the most affected organs include the large blood vessels near the heart which become weak, inelastic and can tear open (this is very bad and can cause immediate death). For Marfan syndrome, which cells produce the elastic fibers? Osteocytes Adipocytes Myocytes Fibroblasts
fibroblasts
Cells: have phospholipid membranes which regulate the passage of molecule into their cytosol have different organelles depending on their function, but must have a nucleus spend most of their lives with their DNA organized as chromosomes divide by meiosis to replace dead or damaged cells
have phospholipid membranes which regulate the passage of molecule into their cytosol
_____ are useful in the skeleton because they remodel most readily in response to stress and efficiently transmit forces while remaining lightweight. trabeculae osteons cortical bone adjacent to periosteum articular cartilages
trabeculae Right! Trabeculae are the struts of spongy bone in the epiphyses and adjacent to the medullary cavity. They are more lightweight than dense compact bone (as evidenced by their many open spaces). In the epiphyses they transmit weight to the more dense compact bone of the diaphyseal cortex. They remodel very rapidly in response to signals (compressive stress/hormonal fluctuations); the proximal femoral spongy bone remodels every 3-6 months but the denser compact bone may take 3-7 years to fully remodel. Osteons are the structural unit of compact bone; compact bone comprises the bulk of the diaphyseal cortex (cortical bone) and the part adjacent to the periosteum. Articular cartilages (cartilage on the end of long bones) do not function for weight bearing as much as they function for friction reduction. They do not remodel in response to stress like spongy bone trabeculae do.
For Neuron Signaling, how does Ca2+ enter neurons? A.Passively using a membrane protein B.Passively without a membrane protein C.Actively using a membrane protein D.Actively without a membrane protein
A.Passively using a membrane protein
Which is true regarding human enzymes? A.They can catalyze reactions over and over again B.They work best at very high temperatures C.They work best at very high pHs D.They can react with many types of substrate
A.They can catalyze reactions over and over again
For Neuron Signaling, how are amino acid based neurotransmitters made A.Via dehydration synthesis B.By hydrolysis C.In the cell's nucleus D.During transcription
A.Via dehydration synthesis
Lamellae are remodeled by: A.endosteum. B.osteocytes. C.canaliculi. D.chondrocytes.
A.endosteum.
Bone tissue (or osseous tissue) is composed of extracellular collagen (a large protein), mineral (calcium salts and other minerals) and bone cells (i.e. osteocytes). Osteogenesis Imperfecta (OI, aka brittle bone disease) is a congenital bone disorder in which a mutation in the DNA results in a change in one monomer of collagen. Improper formation of collagen fibers leads to an irregular arrangement of osseous tissue. This results in brittle, easily broken bones. For OI, how is collagen transported across the cell membrane? Exocytosis Facilitated diffusion Osmosis Active transport
Active transport or Exocytosis
Which of the following is true regarding biomolecules? Carbohydrates prevent unwanted substances entering the cell Enzymes are coded for directly by DNA ATP is a high-energy protein Complex biomolecules are synthesized by hydrolysis
Enzymes are coded for directly by DNA
True or False? During transcription, the small and large ribosomal subunits combine to read the mRNA strand and synthesize an polypeptide (amino acid chain).
False You got it! Translation, not transcription, is the process in which the small and large ribosomal subunits combine to read the mRNA strand and synthesize an polypeptide (amino acid chain). During transcription, an enzyme copies a gene from the DNA on an mRNA molecule.
Which organ is best described as one in which there are some cells, there is more ground substance than extracellular fibers, and the ground substance is solid at maturity? Femur Heart Liver Brain
Femur Correct! The four primary tissue types are epithelial, connective, muscle and neural. Only connective tissues are characterized using the terms ground substance - and of this list, bone (the femur, thigh bone) is the only connective tissue. The brain is composed mostly of neural tissue, the heart is composed mostly of cardiac muscle and the liver is a gland (composed mostly of epithelial tissue).
The enzyme pepsin is responsible for catalyzing the digestion of food proteins in the stomach. Which of the following conclusions would be most logical? Food proteins are unable to cross the membranes of digestive cells unless digested. Pepsin is destroyed in the process of digesting food proteins. Pepsin will continue digesting proteins as they move through the small intestine and large intestine. Pepsin is also able to digest cellulose.
Food proteins are unable to cross the membranes of digestive cells unless digested. That's right! Much of what we consume, include protein, is too large to be absorbed into our digestive cells. We reply on digestive enzymes to catalyze the digestion of these foods so that we can absorb their components. Enzymes are substrate specific; that means their active site is formed to fit only one particular type of substrate and that is the only reaction they can catalyze. Enzymes are not used up or destroyed by the reactions that they catalyze, but can be use again and again unless they become denatured. Denaturing occurs when enzymes are exposed to pH or temperature out of their optimal range. An enzyme that functions in the very acidic environment of the stomach would likely be denatured in the neutral small intestine.
Bone tissue (or osseous tissue) is composed of extracellular collagen (a large protein), mineral (calcium salts and other minerals) and bone cells (i.e. osteocytes). Osteogenesis Imperfecta (OI, aka brittle bone disease) is a congenital bone disorder in which a mutation in the DNA results in a change in one monomer of collagen. Improper formation of collagen fibers leads to an irregular arrangement of osseous tissue. This results in brittle, easily broken bones. For OI, which of the following would be at the same level of organization as collagen? Liver Red blood cell Glycogen Sodium ions
Glycogen
Where do you find the cells that act to remodel or maintain bone? In osteon lacunae In the periosteum found covering bones In the endosteum found lining the medullary cavity Lining the central canal of the osteon In all of the listed structures
In all of the listed structures Right! Bone is a dynamic tissue that remodels in response to stress and hormones. Osteoblasts and osteocytes act to build bone, an important feature of bone remodeling. Osteoclasts chew old bone and remove it from where it is not needed. Bone remodeling reshapes the bone while bone maintenance redeposits and renews old bone. The endosteum is a layer of osteoblasts, osteoclasts and osteoprogenitor cells that actively remodel bone. The endosteum is located in the central canal and covering all the trabeculae inside a bone. It is adjacent to the medullary cavity as well. The periosteum consists of the same cells (inner layer of periosteum) although it is located on the outside of bone, adjacent to the outermost compact bone. When bones get thicker or thinner, it is by both endosteal and periosteal deposition or removal. Osteocytes maintain the matrix and can act to build new bone. All the cells mentioned are found in the endosteum and periosteum, although only osteocytes are located in lacunae.
You find a tissue that has the following characteristics: avascular cells contain nuclei, rough ER, golgi apparatuses and mitochondria cells are widely spaced from one another Where did this sample likely come from? Brain Mammary gland Intervertebral disc Osteon
Intervertebral disc Right! The description of this tissue is avascular, cells contain nuclei, rough ER, golgi apparatuses and mitochondria the cells are widely spaced from one another. Of the four primary tissue types, epithelia and some connective tissues are avascular (cartilages). Neural tissue (the brain) and osteons (bones) are highly vascular, so these two answers are out. The described tissue has cells that make proteins for export (rough ER, golgi etc), so a mammary gland may be possible (breast milk contains protein), but so is an intervertebral disc. The intervertebral discs are made of fibrocartilage and they have extracellular protein fibers that are made by chondrocytes. The defining character here is the cells that are widely spaced from one another. In glands, the tissue cells are attached to one another and there is no extracellular material. In connective tissues, the cells are widely spaced from one another by ground substance, as described here. The best answer is the fibrocartilaginous intervertebral disc.
The liver is a glandular organ that functions to secrete many substances to the blood or digestive tract, detoxify chemicals and synthesize molecules utilized by all the cells of the body. What do you think is its likely histologic composition? It is mostly epithelial tissue It is mostly cardiac muscle It is mostly connective tissue It is mostly neural tissue
It is mostly epithelial tissue Right! The liver is the largest gland in the body and is mostly specialized epithelial cells. It is definitely not neural tissue - only the brain, spinal cord and nerves are neural tissue. It is definitely not cardiac muscle tissue - cardiac muscle tissue is specialized for movement and is only found in the heart. You might suspect that the liver is connective tissue. However, you may remember that glands are epithelial tissue. The more organelles you can pack into a cell, the more that cell, and therefore that gland can do. Liver cells are large and well supplied with organelles to perform the liver's many functions (lots of rough and smooth ER and golgi apparatuses).
Neurons are specialized for communication. They are capable of sending electrical signals due to the presence of many ion channels and pumps on the cell membrane that they constantly maintain or replace as needed. Which of the following would be NOT consistent with this information? Neurons are anucleate (they do not have nuclei) Neurons are very permeable to certain ions Neurons have many rough ER Neurons have a high ATP demand
Neurons are anucleate (they do not have nuclei) Right! Neurons (nerve cells) are very active tissue cells that send signals throughout your body. For the nervous system to communicate with a muscle cell or gland, a nerve cell must physically extend all the way to the target. Along the length of the nerve cell, the cell membrane is populated with many ion channels and pumps (pumps move substances against a concentration gradient and require energy to operate). These pumps and channels are proteins that the neuron must construct for itself and insert into the cell membrane. To make these membrane proteins, the neuron uses its abundant rough ER and its nucleus. There are so many rough ER in neurons they have a special name - Nissl bodies - named for a German neurologist. The presence of the many ion pumps in a neuron means that the neuron uses lots of ATP. A full 2/3rds of neuron ATP use is for these pumps alone! The nucleus is required for the production of the membrane proteins (by directing the cell to make these proteins or expressing the recipe for the proteins themselves). Anucleate means "without a nucleus" and this would be inconsistent with the needs of the neuron. The only anucleate cell that we talk about is the red blood cell and it does have a nucleus for a time during its lifespan (the time when protein production is occurring).
In anatomy, collateral means accessory, subordinate, secondary, serving to support or reinforce. Knowing this, where would you expect to find the tibial collateral ligament? On the lateral aspect of the elbow On the lateral aspect of the knee On the medial aspect of the elbow On the medial aspect of the knee
On the medial aspect of the knee Right! Collateral ligaments are groupings of ligaments that function together to support joints. Of the choices listed here, you can eliminate anything having to do with the elbow. Ligaments around the elbow joint should be named ulnar or radial because they are the bones in that area. This leaves us with the knee. In the leg, the fibula is lateral and the tibia is medial. As such, the tibial collateral ligament is found on the medial aspect of the knee. The fibular collateral ligament is on the lateral aspect. This question was really asking you anatomy of the upper and lower limb, but also forced you to apply your understanding of general joint anatomy.
Cancers are more common in tissues with high rates of mitotic division. Based on this information, which of the following tissues would be most likely to develop cancerous tumors. Skin epithelium Skeletal muscle Neural tissue Cardiac muscle
Skin epithelium Correct! Our skin epithelium is subject to a lot of external abrasion and must replace itself frequently. Consequently, skin epithelial cells have high rates of mitotic division, which can contribute to a higher likelihood of errors in the control mechanism for cell division and result in cancer. Frequent, direct exposure to UV radiation also contributes to higher rates of cancer in skin epithelial tissues. Neural, skeletal muscle and cardiac muscle tissues are composed of cells with much lower rates of mitotic division. Though they can develop tumors, they are less common.
Sodium is more concentrated outside of cells than inside cells. What would happen if the cell membrane permeability to sodium suddenly changed? Sodium rushes into the cell passively (net inward movement) Sodium rushes out of the cell passively (net movement outward) Nothing - sodium still does not cross the cell membrane
Sodium rushes into the cell passively (net inward movement) Right! Membrane permeability to an ion can change when a gated ion channel opens and the ion can then cross the cell membrane. Sodium ions are more concentrated outside of all cells because the sodium-potassium pump constantly moves 3 sodium ions out of the cell while moving 2 potassium ions into the cell. This activity uses ATP. Because sodium ions are so concentrated outside the cells compared to the inside, when allowed though a channel, the sodium will rush passively down its concentration gradient and enter the cell (passively means that no ATP must be used by the cell to move the ion). Sodium will not flow passively out of the cell because nature does not favor more sodium being located outside the cells. Nature favors equilibrium - an equal amount of sodium inside and outside. Because there is so much sodium outside the cell and so little inside, passive movement of sodium permits only net movement of sodium into the cell. Something will happen when the membrane permeability changes, but that something will be whatever nature favors.
What is the difference between spongy and compact bone? Spongy bone and compact bone are microscopically arranged differently Spongy bone and compact bone are made of different matrix material Spongy bone and compact bone contain different cellular populations Spongy bone and compact bone are not both found in long bones
Spongy bone and compact bone are microscopically arranged differently Spongy bone and compact bone are made of the same matrix material (1/3rd collagen, 2/3rds mineral), contain the same cellular populations (osteoblasts, osteoclasts, osteocytes, osteoprogenitor cells) and are both found in long bones. Microscopically, the matrix arranges itself as osteons in compact bone, but as non-osteon, irregular lamellae of trabeculae in spongy bone.
When the suffix -clast is present, it refers to a cell that destroys - for example, a chondroclast is a cell that destroys cartilage. When the suffix -blast is present, it refers to a cell that builds - for example, a chondroblast is a cell that builds cartilage. Now answer: In the normal 30 year old skeleton, osteoclast activity is matched by osteoblast activity. What would happen if osteoclast activity was greater than osteoblast activity? The bones would become weaker The bones would become stronger There would be no effect on the skeleton
The bones would become weaker Right! Osteoclasts break down bone (chew it up), osteoblasts build new bone. Since bone is continually remodeled by constant action of the osteoblasts and osteoclasts, if the osteoclasts are destroying faster than the osteoblasts can build, the skeleton will become weaker. This is exactly what happens in osteoporosis.
Suppose you are a cytologist and you are examining an cell under the microscope. You observe that inside the cell there are many flattened, sac-like structures, many of them with small round granules. Based on this information, which of the following conclusions would be most logical? The cell produces many proteins for export. The cell is incapable of cellular division. The cell lacks a cell membrane. The cell is capable of motion.
The cell produces many proteins for export. Right! The best answer here is that the cell makes proteins for export. The description given in the question is suggestive of an organelle that has flat sacs and ribosomes attached to them - the rough endoplasmic reticulum (rough ER). This organelle is responsible for protein production. These proteins might leave the cell or become incorporated into the cell membrane. The other options in this question may be true, but the only information you were given was about the rough ER and the question states "Based on this information..." It would not be logical to conclude no cell membrane - the cell would not be in very good shape to examine in the scope without a cell membrane. There was no mention of a flagellum or of centrioles, therefore motion and cellular division are unusual conclusions at best.
Which of the following would be most likely found in a cell that is subjected to significant mechanical strain (such as a cell in the outer skin)? The cell would have many cytoskeletal elements The cell would have many smooth ER The cell would have many golgi apparatuses The cell would lack phospholipids in its cell membrane
The cell would have many cytoskeletal elements Yes! Cytoskeletal elements help give support and structure to cells. In particular, keratin is a protein string (cytoskeletal element) found in great quantity in skin cells. The keratin provides strength to skin cells to resist mechanical stresses. The keratinized skin cells are regularly lost from the body surface and replaced with cells in deeper layers of the skin. Smooth ER is used for making fats or carbohydrates (or combinations of those) or acts as an intracellular storage site. It is not the best choice here. Golgi are not the best choice here because they serve to repackage materials that do not remain in the cytoplasm. Phospholipids contribute significantly to the cell membrane and without them, the cell is unlikely to be functional. In answering questions you must always assume a healthy adult unless otherwise indicated.
Apocrine sweat glands, like those in the armpit, produce a watery secretion rich with pheromone oils. Which of the following best describes the cells of these glands that export these secretions? The cells contain smooth ER and golgi apparatus The cells contain ribosomes and nuclei The cells have golgi apparatus and many lysosomes The cells have many cytoskeletal elements
The cells contain smooth ER and golgi apparatus
In bones, a layer of osteoblasts and osteoclasts line the interior of the bone (this cellular layer covers all trabeculae, is adjacent to the medullary cavity and lines the inside of osteons). This layer is called the endosteum. What is its role in bone? The endosteum can add or remove bone from the inside of bones, remodeling them. The endosteum can add or remove cartilage from the inside of bones, replacing bone with cartilage. The endosteum is an epithelial layer that protects the inside of bones and regulates transportation of nutrients to bones. The endosteum has collagen fibers that anchor attaching muscles.
The endosteum can add or remove bone from the inside of bones, remodeling them. Right! The endosteum is made of connective tissue cells (not epithelial cells) that can deposit or reabsorb bone from the internal aspect of the bone. During growth, the endosteum is particularly important to remodel bone from the inside. Without endosteal bone reabsorption, as bones grow wider overall, the bone would become too heavy. In other words, as bones grow wider (due to periosteal bone deposition), they maintain the same cortical bone thickness because of endosteal removal. Cartilage is deposited by chondroblasts. Muscles attach at the outside of bone on the fibrous layer of the periosteum.
Which of the following determine the function of an anatomical structure?
The material that composes the structure
The periosteum is a double layered structure on the outside of all bones. The outermost layer is a fibrous connective tissue, the innermost layer (adjacent to the cortical bone) is a layer of osteoblasts, osteoclasts and osteogenic/osteoprogenitor cells. What are the two roles of the periosteum? The outer fibrous layer regulates nutrient/waste transfer; the inner cellular layer makes the bone flexible The outer fibrous layer makes the bone flexible; the inner cellular layer regulates nutrient/waste transfer The outer fibrous layer deposits or removes bone; the inner cellular layer attaches muscle The outer fibrous layer attaches muscle; the inner cellular layer deposits or removes bone
The outer fibrous layer attaches muscle; the inner cellular layer deposits or removes bone Right! The periosteum's outermost layer is a dense irregular connective tissue in which collagen fibers are oriented at varying angles (hence the name, dense - lots of fibers; irregular - fibers at many angles). This creates good tensile strength to resist the pull of the many muscles attaching at different angles. The collagen fibers in this layer blend with the fibers of muscle tendons and with the outermost compact bone. By blending together, the muscles attach very firmly to both the periosteum, which is then firmly anchored to the bone - it is more typical to tear a muscle in the middle of its belly than to tear it off the periosteum. The name of the connecting fibers between the periosteum and bone are called Sharpey's fibers. The cells of the inner periosteal layer are essential for bone remodeling. As bones grow in length, they need to add mass to the outer circumference of a bone and they need to be able to remove bone where it is not needed. Bone is alive and requires resources to maintain it. The periosteum helps balance the needs of the body for strong bones that are of the right construction for maximal efficiency of use.
What characteristic unites all connective tissue? They all come from a common embryonic tissue (mesenchyme) They all have a rich blood supply They all have osteocytes They all have liquid ground substance
They all come from a common embryonic tissue (mesenchyme) Connective tissues vary widely in anatomy. Some have many collagen fibers (dense regular connective tissues), some have few fibers (blood). Some are solids (bone) some are loose and stringy (areolar CT). The single unifying component among all connective tissues is their common originating tissue - all connective tissues come from a stem cell tissue called mesenchyme. Mesenchyme is found in embryos - it is made of mesenchymal cells and a fluid ground substance with a few fibers. These cells can differentiate to become bone cells or cartilage cells or blood cells or any other connective tissue cell. Not all connective tissues have a rich blood - cartilage is avascular and this is why it is slow to heal. Not all connective tissues have a hard ground substance - bone does, but blood is all liquid. Bone has osteocytes - they are the cells of bone (osteo=bone, cyte=cell). It is those cells that make the fibers in bone.
How do ions move from low concentration to high concentration?(Against a concentration gradient) Using cellular energy (ATP) Passively, by diffusion
Using cellular energy (ATP) Right! Because nature favors equilibrium, ions that are clustered together will bounce off of each other very frequently and move away until they are evenly separated from one another. To then move ions to where they don't really want to be (not energetically favorable), you must use ATP. I think of this like pumping water from a well - gravity pulls water to the bottom and to overcome gravity, you must use energy to bring the water up. ATP dependent pumps are used by cells to move ions against a concentration gradient (from low to high; also called uphill or against a concentration gradient).
When you are lying prone on the beach getting a good tan while studying your anatomy textbook, which of the following anatomical structures is considered anterior? Your dorsal thigh The calf (sura) The point of the elbow (ulna) Your navel (umbilicus, belly button) You cannot tell from this information.
Your navel (umbilicus, belly button) No matter what your actual position, anatomical position refers to the individual standing erect, facing forward, feet on the ground, palms open with thumbs turned outward. Regardless of the actual position that this question describes, all anatomical language and relationships are in reference to anatomical position. In anatomical position, the umbilicus is anterior, the calf, elbow point and dorsal thigh are all posterior.
Endochondral ossification: starts with a fibrocartilage precursor. begins with mesenchymal cells in the area that differentiate into osteoblasts. involves the formation of spongy bone first, and then compact bone is laid down around it by the periosteum. begins when osteoblasts are delivered by blood vessels.
begins when osteoblasts are delivered by blood vessels. Right! Endochondral bone formation requires blood vessels to form and deliver osteoblasts to the site of ossification. A hyaline cartilage (not fibrocartilage) protobone exisits. The chondrocytes in that proto bone cannot become osteoblast; the osteoblasts must be brought in. These first osteoblasts begin to form the bony collar, which is the periosteum. As the bone collar grows, the cartilage within it begins to dye. Bone continues to grow from the primary ossification center in the diaphysis until maturity. In intramembranous bone formation, mesenchymal cells in the area differentiate to form osteoprogenitor cells and eventually osteoblasts.
During formation of the flat portions of the frontal bone, ______ differentiate to become _______. mesenchymal cells; osteoblasts osteoblasts; osteoclasts osteoprogenitor; osteoclasts mesenchymal cells; chondroblasts
mesenchymal cells; osteoblasts Right! Certain bones form intramembranously - these include the flat skull bones of the cranium, the clavicle and the mandible. During intramembranous bone formation, mesenchymal cells in the mesenchyme differentiate to become osteoblasts. Differentiation refers to a non-specific stem cell developing into a specific cell type. Mesenchyme in the embryo is a tissue that contains mesenchymal cells and extracellular fibers and fluid. During development, specific cellular signals cause the mesenchymal cells in the appropriate areas to cluster and then differentiate into osteoblasts. The newly formed osteoblasts deposit bone which eventually morphs into the above mentioned bones. Osteoblasts are derived from osteoprogenitor cells which are derived from (differentiate from) mesenchymal cells. Chondroblasts are also derived from mesenchymal cells, but they deposit cartilage, not bone. This process occurs during endochondral bone formation. Osteoprogenitor cells do not give rise to osteoclasts (the bone destroying cells). While osteoclasts are active during bone growth and remodeling, they are derived from the white blood cell line, not the osteoprogenitor cell line.
Bone tissue (or osseous tissue) is composed of extracellular collagen (a large protein), mineral (calcium salts and other minerals) and bone cells (i.e. osteocytes). Osteogenesis Imperfecta (OI, aka brittle bone disease) is a congenital bone disorder in which a mutation in the DNA results in a change in one monomer of collagen. Improper formation of collagen fibers leads to an irregular arrangement of osseous tissue. This results in brittle, easily broken bones. For OI, the provided evidence suggests that: molecular function is affecting atomic function. tissue function is affecting organismal structure. tissue structure is affecting cell structure. molecular structure is affecting organ function.
molecular structure is affecting organ function.
If blood pressure gets too low, receptors in the major arteries send a signal to the brain. The brain then sends a chemical messenger to the heart to increase its pumping rate and restore appropriate blood pressure. This is an example of:
negative feedback
The condition Marfan syndrome is a genetic disorder that affects proper production of the extra-cellular matrix protein fibrillin-1. Fibrillin-1 is necessary for proper production of elastic tissue fibers in the extracellular matrix, though other matrix fibers of these tissues are not affected. When elastic fibers are not properly formed, certain organs are severely affected. In extreme cases, the most affected organs include the large blood vessels near the heart which become weak, inelastic and can tear open (this is very bad and can cause immediate death). For Marfan syndrome, which organelles produce fibrillin-1? Rough ER Free ribosomes Smooth ER Mitochondria
rough er
Carbohydrates are: the preferred energy source most body cells. broken down through the process of dehydration synthesis. the main source of enzymes in the body. stored as cellulose in the human body.
the preferred energy source most body cells. Yes! Most cells in the human body use glucose as their primary energy source. Molecules are built by dehydration synthesis and broken down by hydrolysis. Enzymes are proteins, made of amino acids, not carbohydrates. In the human body, carbohydrates are stored as glycogen, not cellulose (cellulose is found in plants!).
