Final exam Flashcards
What is anatomy?
The systematic/scientific study of body structure.
What is physiology?
The scientific study of body function
What are the subdivisions of anatomy?
Gross anatomy, microscopic anatomy, and developmental anatomy.
Gross anatomy is also called…
Macroscopic
What is gross anatomy?
The study of structure where you don’t need any instruments, you can use the naked eye.
What are 3 subdivisions of gross anatomy?
Regional anatomy, systemic anatomy, and surface anatomy.
What is regional anatomy?
The study of structures which are belonging to any particular region.
What is systemic anatomy?
The study of structures that belong to a particular system.
What are the subdisciplines of physiology?
Neurophysiology, endocrinology, and pathophysiology.
What is neurophysiology?
The physiology of the nervous system.
What is endocrinology?
The physiology of hormones.
What is pathophysiology?
Mechanisms of disease.
What is immunology?
The study of the immune system.
What are the 6 levels of structural organization?
Chemical level, cellular level, tissues, organs, organ systems, and organism.
What is the first level of structural organization? What is it composed of?
Chemical (molecular) level. It’s composed of atoms and molecules.
What is the second level of structural organization? What is it composed of?
Cellular level. It is composed of cells.
What is the first level of life in structural organization?
Cellular level.
What is the third level of structural organization?
Tissues
What are tissues?
Tissues are groups of cells with similar structure and functions.
What is the fourth level of structural organization?
Organs
What is the fifth level of organization?
Organ systems
What is the sixth level of structural organization?
Organism
How many organ systems are there?
11
What are the 11 organ systems?
- Integumentary system
- Skeletal system
- Muscular system
- Nervous system
- Endocrine system
- Cardiovascular system
- Lymphatic system
- Respiratory system
- Digestive system
- Urinary system
- Reproductive system.
What is an organ system?
Body organs that have similar or related functions.
What are body cavities?
Cavities mean space. Spaces in the human body are called body cavities.
What cavities make up the posterior (dorsal) cavity?
The cranial cavity which houses the brain. And the spinal cavity which houses the spinal cord.
What does the dorsal (posterior) cavity consist of?
Cranial cavity and spinal (vertebral) cavity
What does the ventral (anterior) cavity consist of?
Thoracic cavity and abdominopelvic cavity
What is metabolism?
Internal chemical reactions.
What is responsiveness??
Ability to sense and react to stimuli (irritability or excitability)
What is movement?
Movement of an organism and/or of substances within the organism.
What is development?
Differentiation and growth
What is reproduction?
Producing copies of themselves; passing genes to offspring.
What is homeostasis?
The capacity of the body to maintain a stable internal environment in spite of fluctuating external conditions. * The ability to detect change, activate mechanisms that oppose it, and thereby maintain relatively stable internal conditions.
Not maintaining homeostasis will lead to _____ or ______. Further non maintaining will lead to _____.
Illness or disease. Death.
What are the components of homeostasis?
Variables, stimulus, receptors, control center, effectors, and effects.
What is a variable?
It’s a measurement; a number.
What’s a stimulus?
A change in variable; change in the number.
What is a receptor?
Specialized nerve endings which respond to the stimulus.
What do receptors do after picking up the stimulus?
They can’t do anything so they take it to the control center.
What is the control center?
The two control systems are nervous and endocrine.
Which controls system works faster, nervous or endocrine? Why?
The nervous system works faster because it uses immediate electrical impulses while the endocrine system uses hormones.
What are effectors?
Nerve signals, hormones.
What are effects?
Changes in target organs.
What are the two kinds of feedback mechanisms?
Negative and positive
What is negative feedback mechanism?
When there is a see saw effect in change. The stimulus and the effect go in opposite directions (the stimulus goes up while the effect goes down. Or the stimulus goes down while the effect goes up).
Negative feedback serves to…
Reduce an excessive response and keep a variable within the normal range.
What is positive feedback mechanism?
When there is greater change in the same direction. Both the stimulus and the effect go in the same direction (they both either go up or they both go down).
Positive feedback serves…
To intensify a response until an endpoint is reached.
What are feedback loops?
Because feedback mechanisms alter the original changes that triggered them, they are called feedback loops.
What is the importance of maintaining body functions? (Importance of maintaining homeostasis)
Not maintaining homeostasis will lead to illness or disease. Further non maintaining will lead to death.
What is negative feedback?
When there is a see saw effect in change. The stimulus and effect go in opposite directions. When the stimulus goes up, the effect goes down. When the stimulus goes down, the effect goes up.
What is positive feedback?
When there is a greater change in the same direction. The stimulus and effect either both go up or both go down.
What is standard anatomical position?
It’s the reference point. The body is standing or laying supine (laying down) with the head and feet facing forward, arms laying by the sides with the palms facing forward. Thumbs are away from the midline.
Directional terms: right, left
It’s always the patient’s right/left, pictures right/left, animal’s right left, etc. NOT your right/left.
Directional terms: anterior (ventral), posterior (dorsal)
Anterior means the front side. Posterior means the behind or back side.
Directional terms: superior (cranial), inferior (caudal)
Superior means towards the head end. Inferior means toward the leg or tail end.
Directional terms: superficial, deep
Superficial means closer to the surface of the skin. Deep means further from the surface of the skin.
Directional terms: afferent (sensory), efferent (motor)
Afferent means coming in; bringing in sensations. Efferent means going away; taking information away.
Directional terms: ipsilateral, contralateral
Ipsilateral means same side. Contralateral means opposite side.
Directional terms: medial, lateral
Medial means any line which is closer to the midline (median). Lateral means away from the midline.
Directional terms: proximal, distal
Proximal means closer to the point of attachment. Distal means further from the point of attachment.
Directional terms; parietal, visceral
Parietal means closer to the body wall. Visceral means closer to the organs.
What are body planes?
Imaginary lines on the human body.
What are body sections?
When you make cuts along the imaginary lines.
What are the 3 body planes and body sections?
Frontal (coronal), sagittal, and transverse.
What are frontal (coronal) planes and sections?
They divide the body into anterior and posterior halves. * vertical
What are sagittal planes and sections?
They divide the body into right and left halves. *vertical
What are the 2 sagittal sections?
Midsagittal and parasagittal
What is midsagittal?
Equal right and left halves
What does parasagittal mean?
Unequal right and left halves
What are transverse planes and sections?
They divide the body into superior and inferior halves. *horizontal
How many main body cavities does the human body have? What are they?
2 main body cavities. They are anterior (ventral) cavity and posterior (dorsal) cavity.
What cavities make up the anterior (ventral) cavity?
Thoracic cavity and abdominopelvic cavity.
What is the thoracic cavity?
It is divided into 2 cavities. The pericardial cavity which houses the heart. And the pleural cavity which houses the lungs.
What is the abdominopelvic cavity?
Bony pelvis. Divided into 4 quadrants by physicians and divided into regions by anatomists.
What separates the thoracic cavity and the abdominopelvic cavity?
The skeletal muscle called the diaphragm.
What muscle separates the cranial cavity and spinal cavity?
None
The posterior cavity organs are covered by a connective tissue called…
Meninges
The right side of the diaphragm is at a slightly higher level because of the…
Liver
What major organ (viscera) is in the cranial cavity?
The brain
What major organ (viscera) is in the vertebral (spinal) cavity?
The spinal cord
What is the thoracic cavity divided into?
The pleural cavity and the pericardial cavity
What major organ (viscera) is in the pleural cavity?
The lungs
What major organ (viscera) is in the pericardial cavity?
The heart
What major organs (viscera) are in the abdominal cavity?
The digestive organs (stomach, liver small and large intestine), spleen, and kidneys
What major organs (viscera) are in the pelvic cavity?
Bladder, rectum, and reproductive organs
What is mediastinum?
The thoracic cavity is divided by a thick median wall called the mediastinum. This is the region between the lungs. It is occupied by the heart, major blood vessels connected to it, esophagus, the trachea and bronchi, and a gland called the thymus.
What are the 9 regions of the abdominopelvic cavity?
Left hypochondriac region, left lumbar region, left inguinal (iliac) region, epigastric region, umbilical region, hypogastric region, right hypochondriac region, right lumbar region, and right inguinal (iliac) region.
What are the 4 quadrants of the abdominopelvic cavity?
Right upper quadrant (RUQ), left upper quadrant (LUQ), right lower quadrant (RLQ), and left lower quadrant (LLQ).
What is the plasma (cell) membrane?
The outer limiting layer of the cell. It surrounds the cell and defines the boundaries.
What is the plasma (cell) membrane made of?
Proteins and lipids
What is cytoplasm?
Gelatinous liquid that fills the inside of a cell.
Why are the basic parts of a cell?
The plasma (cell membrane), the nucleus, and the cytoplasm.
Describe the plasma (cell) membrane.
It is flexible, thin, 7-10nm in thickness, and a sturdy barrier between the inside and the outside of a cell.
What 2 things do you ALWAYS have to remember about plasma (cell) membrane?
Semipermeable, and fluid mosaic model
Cell membranes are semipermeable, meaning…
Molecules can move through them.
What is the nucleus?
It is the command/control center of a cell
All cells have a…
Nucleus with a few exceptions
Cells usually have 1 nuclei so they are…
Uninucleate
A cell with no nucleus is called…
Anucleate. Examples are RBC (red blood cells) and platelets.
What 2 things do you ALWAYS have to remember about plasma (cell) membrane?
Semipermeable, and fluid mosaic model
What is fluid mosaic model?
It describes the structure of the plasma membrane as a mosaic of components - including phospholipids, cholesterol, proteins, and carbohydrates - that gives the membrane a fluid character
What is cytoplasm composed of?
Cytosol and organelles
Plasma (cell) membrane has ______ faces and _______ faces.
Intercellular faces and extracellular faces.
What are the 3 functions of the plasma membrane?
Defines cell boundaries
Governs interactions with other cells
Controls passage of materials in and out of cell.
98% of the plasma (cell) membrane molecules are…
Lipids
What are lipids?
Fats
75% plasma (cell) membrane lipids are…
Phospholipids
A plasma membrane is made up of ___ layers of _____ called the _____.
2 layers of phospholipids called the bilayer
Amphipathic molecules arranged in a bilayer means…
There is a water loving and water hating phospholipid in the same layer.
Most transmembrane (integral) proteins are…
Glycoproteins
What are the arrangements of peripheral proteins?
They do not protrude into the phospholipid layer but adhere to the inner or outer face of the membrane. They are usually tethered to the cytoskeleton.
These amphipathic molecules arrange themselves…
Into a sandwich like bilayer, with their hydrophilic phosphate-containing heads facing the water in each side and their hydrophobic tails directed toward the center, avoiding the water.
What are the 2 broad classes of protein membranes?
Transmembrane (integral) proteins and peripheral proteins
The heads on phospholipids are…
Hydrophilic
Hydrophilic means…
Water loving
The tails on phospholipids are…
Hydrophobic
Hydrophobic means…
Water hating
Phospholipids drift _____, keeping the membrane _____.
Laterally, fluid
What are the 3 lipids?
Phospholipids, cholesterol, and glycolipids
Phospholipids make up ___ of the membrane layer.
75%
Cholesterol makes up ___ of the membrane layer.
20%
Glycolipids make up ___ of the membrane layer.
5%
What does cholesterol do?
They hold phospholipids still and can stiffen the membrane.
Cholesterol looks like…
4 ring-like structures linked.
Cholesterol are _____ in between the ________.
Wedged, fatty acid tails
____ of cholesterol needed for all cells is created by the _____.
85%, liver
Glycolipids are only found on…
The extracellular surface of a cell
Glycolipids are…
Nothing but sugars attached to liquid.
Glycolipids are attached to…
The fatty acid tails
Glycolipids look like…
Tree branches. 8 ring-like structures linked.
Glycolipids + glycoproteins =
Glycocalyx
What is glycocalyx?
Carbohydrate coating on cell surface. It helps with understanding.
What is the body structure of lipids (fats)?
Glycerol with 3 fatty acid tails
Phospholipids have ___ fatty acid tails and a ______
2, phosphate
Proteins are the ________ of any cell.
Functioning units
What are glycoproteins?
Integral or transmembrane proteins
What do glycoproteins do?
Penetrate the membrane.
What is the main job of peripheral proteins?
Structural support
Function of the membrane proteins include:
Receptors, enzymes, channels, carriers, cell-identity markers, and cell-adhesion molecules.
What are the function of receptors?
They bind chemical signals. Allows chemical to sit.
What are the functions of the enzymes?
They speed up a chemical reaction. They are not destroyed in the process.
What are the functions of channel proteins?
They allow hydrophilic particles and water to come in and out of the membrane.
What are the functions carrier proteins?
They bind solutes and transfer them across membrane. Transport heavier molecules like glucose, amino acids, vitamins, hormones.
What are the functions of cell-identity markers?
They are glycoproteins acting as identification tags. It distinguished the body’s own cells from foreign cells.
What are the functions of cell-adhesion (linkers) markers?
They mechanically link cell to extracellular material.
What is a permeable membrane?
A membrane that allows all substances to pass through.
What is a selectively permeable membrane?
A membrane that allows some substances to pass through while excluding others.
What is an impermeable membrane?
A membrane that doesn’t allow any substance to pass through.
What is extracellular fluid (ECF)?
Includes any fluid outside of cells.
What are some examples of extracellular fluid (ECF)?
Tissue (interstitial) fluid, blood plasma, lymph, and cerebrospinal fluid. Blood is also an ECF.
What does extracellular mean?
Situated or occurring outside of a cell.
What is interstitial fluid?
Fluid found in the spaces around cells.
What is the function of interstitial fluid?
It helps bring oxygen and nutrients to cells and removes wast products from cells.
What does intercellular mean?
Situated between or among the cells.
What does intracellular mean?
Within the cell.
What is intracellular fluid?
It is the cytosol within the cell.
What are the arrangements of transmembrane (integral) proteins?
They pass completely through the plasma membrane. They are embedded within the plasma membrane. They go through both layers.
What is cholesterol?
Weakly amphipathic. Holds phospholipids still and can stiffen membrane. Look like 4 ring-like structures linked.
Leakage ion channels are…
Always open, specific, more leakage ion channels for potassium than sodium (K>Na)
What do ligand (chemical)-gated channels do?
Respond to chemical messengers
What do voltage-gated channels do?
Respond to charge changes
What do mechanically-gated channels do?
Respond to physical stress on cell; respond to a mechanical stimulus
Channel proteins are crucial to ______ and ______ function
Nerve, muscle
Describe membrane fluidity
Phospholipids drift laterally from place to place, spin on their axis, and flex their tails. These movements keep the membrane fluid.
What does membrane permeability mean?
Diffusion through a membrane depends on how permeable it is to its particles.
What is a concentration (chemical) gradient?
When there is a difference in the concentration/the number/the amount of substances
What is an electrical gradient?
When there is a difference in charges (positive and negative charges).
What is an electromagnetic gradient?
When a molecule moves on the bases of concentration of the chemical and charge
What are gradients?
Gradients are change. They are part of membrane transport
What is membrane transport?
The movement/transport of materials across the plasma membrane of any cell.
Movement down the concentration gradient means…
it goes from high concentration to low concentration and energy (ATP) is not used.
Movement against the concentration gradient means…
It goes from low concentration to high concentration and energy (ATP) is used.
What are the 3 types of passive transport?
Diffusion, osmosis, and filtration.
What is simple diffusion?
Movement of particles from a region of higher to a region of lower until an equilibrium is reached. No ATP (energy). Particles must be small size and lipid soluble.
What is facilitated diffusion?
The carrier-mediated transport of a solute through a membrane down its concentration gradient. It requires no ATP (energy) by the cell. It transports solutes such as glucose that cannot pass through the membrane unaided.
What is membrane potential?
Charge separation happening on either side of the plasma membrane. Positive on the outside, negative in the inside.
The rate of diffusion is affected by:
Temperature
Molecular weight
“Steepness” of concentration gradient
Membrane surface area
Membrane permeability
Diffusion affected by temperature
Higher the temp, faster the rate of diffusion
Diffusion affected by molecular weight (size of molecule)
Greater the molecule size, slower the rate of diffusion
Diffusion affected by “steepness” of concentration gradient
Greater the steepness (difference), faster the rate of diffusion
Diffusion affected by membrane surface area
Greater the surface area, greater the diffusion
Diffusion affected by membrane permeability
Greater the membrane permeability, faster the rate of diffusion
What is osmosis?
Movement of water from a region of high to a region of lower water concentration through a semipermeable membrane.
What is a solute?
Particle
What is a solvent?
Water
Solute + solve =
Solution
What is filtration?
Particles are driven through membrane by physical pressure. Occurs in the blood vessels.
What are the 3 types of active processes?
Primary, secondary, and vesicular.
What is primary transport?
Sole user of energy.
What is an example of primary transport?
Na K ATPase pump
What is secondary transport?
It is dependent on the primary. If the primary doesn’t do its job, then the secondary cannot work.
What is an example of secondary transport?
Sodium Glucose Transporters (SGLT)
What is vesicular transport?
Moves large particles or numerous molecules at once through the membrane, contained in bubble-like vesicles of the membrane.
What is kinetic energy?
Kinetic energy is the energy an object has because of its motion.
What is the role of kinetic energy in diffusion?
Diffusion is driven by kinetic energy.
What is the difference between simple diffusion and facilitated diffusion?
Simple diffusion allows the direct transport of molecules across the cell membrane. In contrast, facilitated diffusion occurs via transmembrane proteins like carrier proteins and channel proteins.
What is osmolarity?
The total number of nonpermeating solutes/particles in solution
What is tonicity?
The capacity of the solution to change the volume and shape of any cell.
What is an isotonic fluid?
No change in the volume or shape of any cell.
What is hypotonic fluid?
More water, less solutes.
What is hypertonic fluid?
More solutes, less water.
What does crenated mean?
Water has come out. Cell looks like it has spikes.
What does hemolysis mean?
When red blood cells swell which causes them to rupture.
What is osmotic pressure?
The amount of pressure that would have to be applied to one side of a selectively permeable membrane to stop osmosis.
What is the function of the sodium potassium pump?
Sodium is always supposed to be on the outside of the cell. ATPase pump is 3 NA out (3 sodium out), 2 K (2 potassium in) in. The pump uses energy.
By pumping sodium out and potassium in, the Na K ATPase pump maintains…
Membrane potential
What is resting membrane potential?
When there is no big change in the membrane potential.
What is cytosol?
The solution part of the cell. This is the fluid that is found within the cell.
How much of the cell is made up of cytosol?
60%
What is the cytoskeleton of a cell?
A system of protein microfilaments, intermediate filaments, and microtubules in a cell.
What is the function of the cytoskeleton?
Serves in physical support, cellular movement, and the routing of molecules and organelles to their destinations within the cell.
What are microfilaments?
They are thin filaments that are 6 nm thick and are made of the protein actin.
What are intermediate filaments?
They are thicker and and stiffer than microfilaments.
What are the functions of intermediate filaments?
They give the cell its shape, resist stress, and form junctions that attach cells to their neighbors.
What are microtubules?
They are cylinders made up of 13 parallel strands called protofilaments.
What is the Golgi complex?
Its a small system of cisterns.
What are the functions of the Golgi complex?
It synthesizes carbohydrates and puts the finishing touches on proteins and glycoprotein synthesis.
What are ribosomes?
They are small granules of protein and RNA.
Where are ribosomes found?
They are found in the nucleoli, in the cytosol, in mitochondria, and on the outer surfaces of the rough ER and nuclear envelope.
What is a lysosome?
It is a package of enzymes bounded by a membrane.
What is mitochondria?
They are organelles specialized for synthesizing ATP.
What is a centriole?
A short cylindrical assembly of microtubules, arranged in 9 groups of 3 microtubules each.
What is a centrosome?
A small, clear patch of cytoplasm near the nucleus.
What is the endoplasmic reticulum?
It is a system of inner connected channels called cisterns enclosed by a unit membrane.
The endoplasmic reticulum can either be _______ or _______.
Rough or smooth.
What is the difference between rough ER and smooth ER?
The surface of rough ER is covered in ribosomes which makes it rough. The surface of smooth ER doesn’t have any ribosomes.
What is microvilli? What is their primary purpose?
They are extensions of the plasma membrane that serve primarily to increase cell’s surface area.
What are cilia?
Cilia are hairlike processes about 7 to 10 micrometers.
What does a nucleus contain? Which makes it what?
The cell’s chromosomes which makes it the genetic control center of cellular activity.
What is the nuclear envelope?
A pair of membranes enclosing the nucleus of the cell.
The nuclear envelope is perforated with…
Nuclear pores.
What are nuclear pores?
They are formed by a ring of proteins called the nuclear pore complex.
What are chromatin?
Fine threadlike matter composed of DNA and proteins.
What is a nucleolus?
A dark-staining mass where ribosomes are produced.
Histology
The study of tissues
What are the 4 basic tissue types in the human body?
Epithelial, connective, nervous, and muscle.
Epithelial tissue ______ body surfaces and _____body cavities, forms _________, and is __________.
Covers, lines, all glands, avascular.
What are the 6 functions of epithelial tissue?
Protection, secretion, excretion, absorption, filtration, and sensation.
Protection function of epithelial tissue
Protects deeper tissues from injury and infection.
Secretion function of epithelial tissue
Produces and releases mucus, sweat, enzymes, hormones, and other substances.
Epithelial tissue excretion function
Voids waste from the tissues.
Absorption function of epithelial tissue
Absorbs chemicals, such as nutrients.
Filtration function of epithelial tissue
All substances leaving the body are selectively filtered by an epithelium.
Epithelial tissue sensation function
Nerve endings in epithelia detect stimuli.
What is connective tissue?
Most common tissue and highly variable vascular.
Loose connective tissue has ____ blood vessels
Many
Cartilage has ____ blood vessels
No
What are the 8 functions of connective tissue?
Binding of organs, support, physical protection, immune protection, movement, storage, heat production, and transport.
Binding of organs function of connective tissue
Connect one bone to another, muscles to bones, skin to muscle, and holds organs in place.
Support function of connective tissue
Supports the body and it’s organs, forms internal framework of organs.
Physical protection function of connective tissue
Protects and cushions delicate organs
Immune protection function of connective tissue
Connective tissue cells attack foreign invaders
Connective tissue movement function
Bones provide lever system for body movement
Storage function of connective tissue
Maintains stores of fat, calcium, and phosphorus.
Heat production of connective tissue
Metabolism of brown fat generates heat
Transport function of connective tissue
Blood transport gases, nutrients, wastes, hormones, and blood cells.
Muscle tissue is specialized to ________ when ________, exerting a ________ on other ______, ______, or ________. Also an important source of __________.
Contract, stimulated, physical force, tissues, organs, fluid. Body heat.
Excitability
Ability to respond to stimuli by changing membrane potential
What are the general features of epithelial tissue?
Avascular, basement membrane, apical surface, lateral surface, and basal surface.
Epithelial tissue is avascular meaning…
It is also _________ by the __________________.
Has no blood vessels, nourished by underlying connective tissue.
Epithelial tissue rests on the…
Basement membrane
What is epithelial basement membrane?
The basement membrane is made up of 2 layers: basal lamina and reticular lamina.
The basal lamina is made up of _____ and it is ______.
Glycoproteins and it is acellular
The reticular lamina is…
The underlying connective tissue attached to the basal portion.
What is the apical surface of epithelial?
It faces away from the basement membrane (faces the lumen). The apical portion is free.
The apical surface has these fingers called…
Microvilli
The microvilli have eyelash looking things called…
Cilia
You only see sodium glucose transporters at the…
Apical portion
What is the lateral surface of epithelial? It is also called _______.
The surface between the basal and apical surfaces. Its called the “sidewall”.
What is the basal surface of epithelial?
It faces the basement membrane. The basal portion is attached.
You only see Na K ATP pump at the…
Basal portion.
Contrast covering and lining epithelium and glandular epithelium.
Cover and lining epithelium
Simple epithelial have how many layers?
1 layer
Stratified epithelial have how many layers?
Many layers
Pseudostratified epithelial have how many layers?
Falsely appear to have many layers, but only has 1 layer.
Simple squamous cell shapes are…
Thin, scaly cells, and nucleus is squished. They have a fried egg appearance.
Stratified squamous cell shapes are…
Deepest cells are cuboidal to columnar.
Simple cuboidal cell shapes are…
Squarish or round cells, equal length and equal width, and nucleus is round like a bead. String of bead appearance.
Simple columnar cell shapes are…
Tall, narrow cells, and nucleus is oval/elongated.
Transitional (urothelium) cell shapes look like… Why is it called transitional?
stratified squamous, but not as many layers. Topmost layer of cells change, which is why it is called transitional.
Simple squamous permits _________ or _______ of substances, and secretes _________.
Permits rapid diffusion or transport of substances, and secretes serous fluid.
Simple squamous are found in areas where ______ and _______ is required. Found in…
Diffusion and filtration. Found in capillaries, alveoli, glomeruli, and serous
Serous (visceral and parietal layer) is lined by…
Simple squamous
Stratified squamous is…
Filled with a protein called keratin which makes it waterproof and nonadhesive.
What are the two kinds of stratified squamous?
Keratinized and non-keratinized
What do keratinized stratified squamous look like?
Multiple cell layers; cells become flat and scaly towards the surface.
Function of keratinized stratified squamous
Resists abrasion, retards water lost through skin, resists penetration by pathogenic organisms.
Where are keratinized stratified squamous found?
Found on the skin surface (epidermis).
What do non-keratinized stratified squamous look like?
Same as keratinized stratified squamous, but without the surface layer of dead cells.
Non-keratinized stratified squamous function
Resists abrasion and penetration of pathogens.
Where are non-keratinized stratified squamous found?
Found on tongue, oral mucosa, esophagus, and vagina.
Simple cuboidal function
Absorption and secretion, mucus production, and movement.
All glands are what kind of cells?
Simple cuboidal
Where are simple cuboidal found?
Found in liver, thyroid, mammary and salivary glands, bronchioles, and kidney tubes.
Simple columnar function
Absorption and secretion (secretion of mucus).
Where are simple columnar found?
They line the digestive tract (GI tract) only from the stomach to the anal canal. Also found in the uterus, kidneys, and uterine tubes.
Function of transitional (urothelium)
Allows for filling of the urinary tract
Where are transitional (urothelium) found?
Found only in the urinary tract
Endothelium is a _______ layer of _____ called __________ cells that line your ____________ and ___________. They help them ______ and ________ and aid in _________.
Single, cells, endothelial cells, blood vessels, lymphatic vessels. Contract, relax, blood flow.
Mesothelium is a layer of ____ that _____ and _______ organs and tissues in the body. Organs examples:
Cells, covers, protects * the lungs, abdomen, heart, and testes.
What is the roll of goblet cells?
Cells that make mucus. They make a protein mucin; it combines with water to make mucus. Mucin + water = mucus
Gland is a _____ or _____ that secretes substances for use __________________ or releases them for ____________________.
Cell or organ that secretes substances for use elsewhere in the body or releases them for elimination from the body.
Endocrine glands have ___ ducts but do have many ______________. They discrete _____ directly into ______.
No, blood capillaries; hormones, blood.
Examples of endocrine glands (3)
Thyroid, adrenal, and pituitary glands
Exocrine glands _______ their contact with _____________ by way of _____. Surfaces can be ________ or ___________.
Maintain, surface of epithelium, duct. External or internal
Example of external exocrine glands
Sweat glands, tear glands
Example of internal exocrine glands
Pancreas gland, salivary glands
Eccrine (merocrine) glands ________ their products by __________.
Release, exocytosis.
Examples of eccrine (merocrine) glands
Tear, pancreas, and gastric
Apocrine secretion is _______ droplet covered by _______ and ________ buds from cell _______.
Lipid, membrane, cytoplasm, surface.
Example of apocrine secretion
Mode of milk fat secretion by mammary gland cells
Holocrine secretion
Cells accumulate a product and entire cell disintegrates. Secretes a mixture of cell fragments and synthesizes substances.
Examples of holocrine secretion
Oil glands of scalp and skin, and glands of eyelids
General features of connective tissue
Most cells are not in contact with each other, and connective tissue has a highly variable vascularity
What is the most common tissue out of the 4 tissues types?
Connective tissue
Loose connective tissues have…
Many blood vessels
Cartilage has…
No blood vessels
Fibroblasts makes _____ for ___________________
ECM, fibrous connective tissue
Adipocyteextracellular matrix
Areolar tissue, reticular tissue, and blood capillaries
Ground substance
An unstructured material that fills the spaces between the cells. Holds water and large molecules (GAGs, proteoglycans, and glycoproteins)
Fibers give ____________ to ____ in ____
structural support, cells, extracellular matrix
Collagen are ______, _______, _________ fibers that resists ____________.
Long, thick, unbranched, stretching
Collagen is also called ________ because…
White fibers because when they are first made they are white.
Reticular tissue is similar to __________ but they are _______, ________, and they form a _______.
Collagen, thin, branched, network.
Elastic is made of a ________ called ________. They ________ which means they ________ back when ___________.
Protein, elastin. Recoil, stretch, stretched.
Elastic fibers are _____ in color so they are called ______ ________.
Yellow, yellow fibers
Areolar tissue has _______, ________, _______, and __________. They are __________ organized fibers with abundant __________.
Fibroblast, accessory cells, ECM, ground substance. Loosely, blood vessels
Where is areolar tissue found?
Found right underneath the skin (underlies epithelia), in serous membrane, between muscles, in passageways for nerves and blood vessels.
Adipose tissue is mostly made up of _______. Have a ___________ appearance (nucleus pushed to the side). Also have a _____________ appearance because it is made up of mostly adipose cells.
Fat cells. Signet ring. Chicken wire.
What are the 2 types of adipose tissue?
White (or yellow) adipose and brown adipose
White adipose tissue (WAT or white fat) is the most _________ and _________ type in _______.
Abundant, significant, adults.
Functions of white adipose tissue
Provides thermal insulation, cushions organs such as eyeballs and kidneys, secretes hormones that regulate metabolism, and provides energy storage.
White adipose tissue looks like ______-looking cells with _________. ________ pressed against cell __________.
Empty-looking, thin margins; nucleus, membrane.
Brown adipose tissue (BAT or brown fat) is mainly in…
Fetuses, infants and children up to 5 years old.
Brown adipose tissue has a rich ________ and is a ______-generating tissue.
Blood supply, heat-generating
Quantity of fat in adipose tissue gets…
Recycled continuously
Areolar tissue has __________ between the cells and the fibers
Lots of space
Areolar tissue has lots of space, so fluid comes in and sits there. It is called…
Edema
Brown adipose tissue is found in the
Anterolateral neck, anterior abdominal wall, and between the shoulder blades
Reticular tissue is made up of _________ and _________.
Reticular fibers, fibroblasts
Reticular tissue forms the ___________ for _________________
Forms framework for lymphatic organs
Where is reticular tissue found?
Found in highly vascular organs like lymph nodes, spleen, thymus, and bone marrow.
Dense regular connective tissue are…
Densely packed (close together), have parallel collagen fibers, and have a compressed fibroblast nuclei.
Dense regular connective tissue move…
In 1 direction
Where are dense regular connective tissue found?
They are found in tendons. Tendons attach muscles to bones and ligaments hold bones together.
Dense irregular connective tissue
Fibers are pulled close by collagen fibers but are pulled in all different directions. They withstand unpredictable stresses.
Where are dense irregular connective tissue found?
Found in the deeper layer of the skin (dermis of the skin); capsules around joints and organs
Hyaline has ___________________ and no ________________.
Fine collagen fibers. No elastic fibers.
What does hyaline look like?
Clear, glassy appearance because of fineness of collagen fibers.
Function of hyaline: eases _________, holds _______ open, and moves ______ chords.
Joint movement, airways, vocal chords.
What is the most common type of cartilage?
Hyaline
All respiratory cartilages are made up of…
Hyaline cartilage
Where is hyaline found?
Found in articulate cartilage (at ends of bones, needed to reduce friction), costal cartilage, trachea, larynx, and fetal skeleton.
All bones in the embryonic skeleton below the clavicle are made up of…
Hyaline cartilage
Elastic cartilage connective tissue contains an ________ of _______ fibers. Covered with ___________.
Abundance, elastic. Perichondrium.
Function of elastic
Provides flexible, elastic support
Where is elastic cartilage found?
Found in external ear, epiglottis, and Eustachian tube/auditory tube/pharyngotympanic tube.
Fibrocartilage contain large ___________ of ______________.
Large, course bundles of collagen fibers.
Fibrocartilage resists ________ and absorbs _________.
Compression, shock
Where is fibrocartilage found?
Found in between the vertebral bones, pubic symphysis, and mandibular symphysis.
Mucous membrane
Lines the passages that open to the external environment. It’s a wet membrane and often has goblet cells.
Example of a mucous membrane
Digestive tract
Functions of mucous membrane
Absorption, secretion, and protection.
Sublayers of mucous membrane
Epithelium, lamina propria (areolar tissue), and muscularis mucosa (smooth muscle).
Mucous membranes epithelial tissue type
Simple columnar/pseudostratified ciliated columnar
Mucous membrane connective tissue type
Areolar
Serous membrane (serosa)
Lines some internal body cavities that do no open to the external environment. It’s a wet membrane.
Serous membrane produces _______ that arises from _______. It ______ organs and ______ walls of body cavities.
Serous fluid, blood. Covers, lines
Serous membrane epithelial tissue type is _________________ called a ___________ which ______ on a layer of __________ tissue
Simple squamous epithelium, mesothelium, rests, areolar
Serous membrane connective tissue type
Areolar
Serous membrane examples
Pleura, pericardium, and peritoneum
All cells which belong to epithelial tissue rest…
On a basement membrane
Cells belonging to epithelia tissue receive nutrition from the…
Underlying connective tissue
All cells which belong to epithelial tissue are highly…
Innervated
Innervated means
Rigidly supplied with sensory nerve fibers
All cells which belong to epithelial tissue have a tremendous potential to…
Regenerate
Epithelial tissues have a high rate of…
Mitosis
Epithelial tissues are classified based on what 2 things?
The number of layers and the shape of the cells.
All cells touch basement membrane in…
Simple epithelia
Some cells rest on top of others and do not touch basement membrane in…
Stratified epithelia
Chondroblasts make ____ for ________
EMC, cartilage.
Chondroblasts turns into a…
Chondrocyte
Chondrocyte
Mature cell, maintains ECM
Fibroblasts turn into a…
Fibrocyte
Fibrocyte
Mature cell, maintains ECM
Osteoblasts
Makes ECM for bones
Osteoblasts turns into an…
Osteocyte
Osteocyte
Mature cell, maintains ECM
Hematoblasts
Makes ECM for blood
Hematoblasts turns into a…
Hematocyte
Hematocyte
Mature cell, maintains ECM
Adipocytes are ____ cells. They give ________.
Fat, nutrition
When there’s lots of empty space between the cells and the fibers it is called…
Loose fibrous connective tissue
Cartilage connective tissue ECM is…
Firm and flexible.
The Chondroblasts create space around them called…
Lacunae (little lake)
Cartilage is avascular so any injury…
Heals slowly
Membrane
Simple organs that are made up of 2 tissues: epithelial and connective
What are the 3 types of membranes?
Cutaneous, mucous, and serous
Cutaneous membrane
The skin; largest membrane in the body. It’s a dry membrane
Cutaneous membrane is what type of epithelial tissue?
Stratified squamous keratinized epithelial tissue (also called epidermis)
Cutaneous membrane is what type of connective tissue?
Dense irregular connective tissue (also called dermis)
The mesothelium that covers the lungs and chest wall is called…
Pleura
The mesothelium that covers the abdominal organs and the abdominal wall is called…
Peritoneum
The mesothelium that covers the heart is called…
Pericardium
The mesothelium that covers the testes is called…
Tunica vaginalis
What are the 8 functions of the skeletal system?
Support, protection, movement, electrolyte balance, acid-base balance, blood formation, hormone secretion, and triglyceride storage.
What are the general features of a long bone?
They are longer than wider
What are the general features of a flat bone?
They are thin curved plates
What are some examples of flat bones?
Parietal bones of skull, sternum, scapula, ribs, and hip bones
What is the support function of the skeletal system?
Limb bones and vertebrae support the body. Jaw bones support teeth. Some bones support viscera.
What is the protection function of the skeletal system?
Cranial bones protect the brain, vertebrae bones protect the spinal cord, the bones in the thoraces protect the heart, lung etc. The pelvis protects the pelvic cavity organs.
The only organs not protected by bone are the…
Abdominal organs
What is the movement function of the skeletal system?
Limb movements, breathing, and other movements depend on bone
What is the electrolyte balance function of the skeletal system?
Bones are a store house of minerals, especially calcium and phosphorus
What is the acid-base balance function of the skeletal system?
Buffers blood against large pH changes by altering phosphate and carbonate salt levels to maintain an acid-base balance
What is the blood formation function of the skeletal system?
Red bone marrow (red in color) is the chief producer of blood cells
What is the hormone secretion function of the skeletal system?
Bone cells secrete hormones that affect action of insulin and moderate the stress response
What is the triglyceride storage function of the skeletal system?
Most areas of the bone, instead of forming the blood cells, get replaced into fat
Bone that gets replaced into fat is called…
Yellow bone marrow
If there is a need for increased blood cells, the yellow bone marrow can…
Change itself into red bone marrow
What is bone (osseous tissue)?
Connective tissue with the matrix hardened by calcium, phosphate and other minerals
What is mineralization/calcification?
The hardening process of bone
Why are bones classified as organs?
Because they are made up of more than 2 tissues
What is bone made up of?
It is made up of blood, bone tissue, bone marrow, cartilage, adipose tissue, nervous tissue, and fibrous connective tissue
How are bones classified?
Bones are classified on the bases of their length, meaning how long or tall they are
What are some examples of long bones?
Humerus, radius, ulna, femur, tibia, fibula, metacarpals, metatarsal, and phalanges
Bones that don’t fit the long bone and flat bone categories are either…
Short bones or irregular bones
What are the general features of short bones?
Approx. equal length and width
What are some examples of short bones?
Bones of wrist and ankle
What are the general features of irregular bones?
Elaborate shapes. The bones don’t fit in the other categories. They are neither long, short, or flat.
What are some examples of irregular bones?
Vertebrae and some skull bones.
What are the general features of sesamoid bones?
They look like a sesame seed magnified 1000x.
What is an example of a sesamoid bone?
Patella organ kneecap
What the general feature of sutural bones?
Wherever these cranial bones come together (where those zigzag lines come together), when it gets replaced those are called sutural bones.
Where are sutural bones found?
Found in the sutures, especially in the areas of the cranial bones.
Much of a long bone is composed of an outer shell of dense white osseous tissue called…
Compact, dense or cortical bone.
What does the outer shell of a long bone enclose?
A space called the marrow (medullary) cavity.
What does the marrow (medullary) cavity contain?
Bone marrow
At the ends of the bones, what is the central space occupied by?
Spongy bone
What is spongy bone?
Loosely organize bone tissue.
What does spongy bone look like?
It looks like a sponge. It has lots of empty spaces.
How is compact (dense or cortical) bone packed?
It it tightly/closely packed.
Does compact (dense or cortical) bone have a lot of empty spaces?
No, it doesn’t have a lot of empty spaces
Where is spongy bone found?
Found in the center of ends and center of shaft of long bones, and the middle of nearly all other bones.
What does spongy bone appear to be?
It appears to be irregular, but it is not.
What is spongy bone covered by?
Durable compact bone.
How much of the skeleton is compact bone by weight?
Three-fourths
How much skeleton is spongy bone by weight?
One-fourth
What would happen if bone was made up of all compact bone?
The bone would be so dense that we wouldn’t be able to walk. It would be too heavy to move.
What does physis mean?
Growth
What is the shaft of a long bone called?
Diaphysis
What is diaphysis?
A long cylindrical tubular shaft that provides leverage.
How much of the diaphysis is made up of compact bone?
The outer third layer
What is on either side of the diaphysis?
Elongated expanded ends called epiphysis.
What does epiphysis provide?
Strengthens the joint and provides added surface area for the attachment of tendons and ligaments.
The joint surface where one bone meets another is covered with…
A layer of hyaline cartilage called articular cartilage.
What does cartilage enable a joint to do?
Move more easily than it would if bone rubbed directly against each other.
Externally, what is a bone covered with?
Periosteum
What is periosteum?
A tough surface membrane.
What are the 2 layers of periosteum?
Outer fibrous layer of collagen and inner osteogenic layer of bone-forming cells.
What is periosteum made up of?
It is made up of 2 layers and perforating fibers.
What do periosteum perforating fibers do?
They penetrate the underlying bone matrix.
What is endosteum?
It is a thin layer of reticular connective tissue.
What does endosteum line?
It lines marrow cavities and all internal bone surfaces.
Flat bones have a _______ like structure.
Sandwich
What is the sandwich like structure of flat bones?
Inner and outer tables of compact bone enclosing layer of spongy bone in between.
What is the sandwich like structure of flat bones in the cranium called?
Diploe
What is diploe?
It’s the spongy middle layer.
What does the diploe do?
It absorbs shock.
What does the periosteum provide?
It provides strong attachment and continuity from muscle to tendon to bone.
Is articular cartilage covered by periosteum?
No
What is periosteum important for?
The growth of bone and healing of fractures.
What are the functions of flat bones?
Flat bones protect delicate organs such as the brain and heart, and form brood surfaces for muscle attachment, such as the scapula and hip bones.
What are the 4 types of bone cells?
Osteogenic cells, osteoblasts, osteocytes, and osteoclasts.
What are osteogenic cells?
Stem cells
What do osteogenic cells make up?
They make up the bone structure.
What do osteogenic cells arise from?
They arise from embryonic mesenchyme.
What is the function of osteogenic cells?
They multiply continuously (undergo cell division), make other bone cell types, and give rise to osteoblasts.
What are osteoblasts?
Bone-forming cells
Where are osteogenic cells found?
They are found in endosteum and the inner layer of the periosteum.
Where are osteoblasts found?
They are found in the endosteum and the inner layer of the periosteum.
What type of cells are osteoblasts?
Cuboidal epithelium
What can osteogenic cells transform into?
Osteoblasts
What is the function of osteoblasts?
They make ECM for bone. They make ground substance for bone, and make the fibers needed for bone, especially collagen fibers.
What process do osteoblasts perform?
Osteogenesis
What is osteogenesis?
Synthesize soft organic matter of matrix and promote its mineralization.
What does stress on osteoblasts simulate?
It stimulates osteogenic cells to multiply rapidly and increase the number of osteoblasts to reinforce bone
What substance do osteoblasts secrete?
A hormone called osteocalcin.
What is the function of osteocalcin?
It stimulates insulin secretion of the pancreas and increases insulin sensitivity of the adipose (fat cells) and limits its growth.
What can osteoblasts mature into?
Osteocytes
What are osteocytes?
Former osteoblasts that have become trapped the the matrix they deposited. They maintain ECM for bone.
What does it mean that osteocytes maintain ECM for bone?
This means that they make sure that nutrition is received and that waste products are removed.
What are canaliculi?
Little channels that connect lacunae.
What is lacunae?
Tiny cavities where osteocytes reside. Little lakes.
What do canaliculi also act like? What is the function?
Strain sensors. They produce biochemical signals that regulate bone remodeling when we exercise.
What happens when an osteocyte says that the matrix isn’t being maintained?
The osteocytes will send messages to the osteoclasts. They will come and destroy the bone. They eat the area where the matrix isn’t being maintained then osteoblasts will deposit the matrix.
Some osteocytes _____ bone matrix while others ______ it.
Reabsorb, deposit
How do osteocytes act as strain sensors?
When stressed they produce biochemical signals that regulate bone remodeling.
What do osteoblasts and osteocytes secrete?
They secrete a hormone called osteocalcin.
What is osteocalcin a part of?
It’s a part of the body acute stress response. “Flight or fight”
What does osteocalcin do?
It stimulate pancreatic secretion of insulin, increases insulin sensitivity of fat cells, acts on skeletal muscles to promote energy available, influences brain development and function, and male fertility.
What are osteoclasts?
They are bone-dissolving cells.
Where are osteoclasts found?
On the bone surface.
How big are osteoclasts?
140 micrometers in diameter
How many nucleuses do osteoclasts have?
They are multinucleated. Usually 3-4 nuclei, but up to 50.
Why are osteoclasts big and multinucleated?
Because they are made from several stem cells fused together.
What do osteoclasts look like?
They look like old-fashioned pacman with a ruffled border, and this border faces the bone.
What is osteolysis?
Bone resolution or bone dissolving. The breakdown of bone.
Do osteoclasts rise from osteogenic cells?
No
Where do osteoclasts rise from?
They rise from the same bone marrow stem cells that give rise to blood cells.
Where do osteoclasts often reside?
Often reside in pits call resorption bays that they etch into the bone surface.
What combination is bone remodeling a result from?
It’s a combination of osteogenesis by osteoblasts and osteolysis by osteoclasts.
What are the only cells capable of dividing and producing more bone cells?
Osteogenic cells
Who do osteocytes give their waste to?
Blood vessels
What is bone remodeling?
Adjustments in bone shape and density to adapt to stress.
Osteoblasts and osteocytes are also what type of important cell?
Endocrine cell
What action do osteoclasts perform?
Osteolysis
Osteolysis is opposite of what action?
Osteogenesis
The combination of the cells and the ECM is called…
An osteoid
What is an osteoid?
The organic part of the bone.
What is an osteon?
The structural and functional unit of a compact bone.
What is an osteon made up of?
A central (Haversian) canal through which blood vessels enter and leave the bone.
What is lamella?
The ground substance laid out in forms of tubes. Laid down in the bone in the form of concentric rings, placed one behind the other.
What is in the center of the lamella?
A central canal through which blood vessels enter and leave the bone.
What is lamella laid out by?
Osteoblasts
What is ground substance in the bone (especially compact bone) made up of?
It is made up of concentric rings or lamella. So, compact bone is called is also called lamellar bone.
In addition to ground substance, bone ECM is going to be made up of what?
Collagen fibers
For each lamella, what direction do the collagen fibers go?
They go in opposite directions.
What is the advantage of the collagen fibers in lamella going in opposite directions?
If bone is undergoing a twisting force, instead of the bone breaking apart, these collagen fibers are sacrificed. These collagen fibers resist the twist. Also called twister resisters.
The organic matter in bone ECM is synthesized by what?
Osteoblasts
Organic matter makes up how much of the bone?
35%
What is the organic matter of the bone?
Cells, ECM, and collagen fibers
Inorganic matter makes up how much of the bone?
65%
What is the inorganic matter of the bone?
85% hydroxyapatite
10% calcium carbonate
Many inorganic ions
What is hydroxyapatite?
It is a crystalized calcium phosphate salt.
What is the appearance of hydroxyapatite and what does it do?
Looks like needle shaped crystals. The needles give the bone exceptional strength and the capacity to last forever.
What makes bones last forever?
Hydroxyapatite
What direction are the hydroxyapatite needles oriented?
In the same direction as the collagen fibers.
Inorganic salts make up how much of the bone?
65%
What are the inorganic salts in the bone?
Calcium phosphate, calcium hydroxide, calcium carbonate, fluoride, sodium, potassium, and magnesium.
What is the ceramic of the bone and what is the polymer of bone?
Hydroxyapatite and other minerals are the ceramic of the bone. Collagen is the polymer of the bone.
What do collagen and minerals of the bone form?
They form a composite material that provides flexibility and strength.
When bones are deficient in calcium salts, the bones become…
Soft and bend easily.
Without protein, a bone is excessively…
Brittle
What are central canals connected by?
Perforating canals
What is another name for osteon?
Haversian system
What are perforating canals?
Transverse or diagonal passages
What are circumferential lamellae? Where are they located?
They fill the outer region of dense bone. They go around the entire circumference of the bone.
What are interstitial lamella? Where are they located?
They are broken lamellas. They fill irregular regions between osteons.
What are spongy bones made up of?
Spicules and trabeculae
What are spicules?
Lattice of bone slivers.
What are trabeculae?
Irregular bars or beams
What is the appearance of spongy bone?
Sponge-like appearance
What are the spaces of spongy bone filled with?
Red bone marrow
What is the function of spongy bone?
Provides strength wile adding minimal weight.
Where do trabeculae develop in spongy bone?
Along the bone’s lines of stress. They are laid where the bone experiences lots of stress and pulling force.
Are there any well-defined osteons in spongy bone?
No
Does spongy bone have central canals?
No
What is bone marrow?
Soft tissue occupying marrow cavities of long bones, small spaces of spongy bone, and the larger central canals.
What are the 2 types of bone marrow?
Red bone marrow and yellow bone marrow.
Red bone marrow is also called…
Myeloid tissue
What does red bone marrow contain?
Multiple tissues including hematopoietic tissue.
What is hematopoietic tissue?
Tissue that produces blood cells.
Where is red bone marrow found in children?
In every bone
Where is red bone marrow found in adults?
Found in skull, vertebrae, ribs, sternum, part of pelvic girdle, and proximal heads of femur and humerus.
What is the longest and thickest bone in the body?
Femur
Is yellow bone marrow found in children or adults?
Adults
What is yellow bone marrow?
Fatty marrow that does not produce blood.
What can yellow bone marrow transform into in an event of severe/chronic anemia?
Red bone marrow
What are central and perforating canals lined with?
Endosteum
What are osteons separated from their neighbors by?
A cement line
What is the function of a cement line?
Block microfractures of the bone from spreading and minimizes the chance of them causing a large-scale fracture.
What is nutrient foramina?
Minute holes in bone surface that allows blood vessels to penetrate.
Why is nutrient foramina important for bones?
Bones need nutrition and they need their waste products to be removed. For this to be done you need blood vessels to be able to come in. Blood vessels can’t just come into bone because bone is hard. So a space needs to be made.
What do the dendrites of osteocytes maintain?
A two-way flow of nutrients and waste between the central canal and the outermost cells of the osteon.
What is ossification/osteogenesis?
The formation of bone
From conception up to 8-10 weeks of intrauterine life, what is the skeleton made up of?
Clavicle and above are made up of fibrous membrane. Skeleton below the clavicle are made up of hyaline cartilage model.
After 8 weeks of intrauterine life, fibrous membrane is replaced into what? What is this process called? What type of bones are they?
Bone, intramembranous ossification, dermal bones.
After 8 weeks of intrauterine life, hyaline cartilage is replaced into what? What is this process called? What type of bones are they?
Bone, endochondral ossification, chondral bones.
What is the line of separation between the fibrous membrane and the hyaline cartilage in the fetal skeleton?
The clavicle
What are the 2 methods that bone develops?
Intramembranous ossification and endochondral ossification
What bones are produced by intramembranous ossification?
The flat bones of the skull, most of the clavicle, and part of the mandible.
What is intramembranous ossification also important for?
Lifelong thickening and remodeling of long bones.
In intramembranous ossification where the bones are called membranous bones, you must remember the 4 letters: O.C.T.P. What do these letters stand for?
Ossification, calcification, trabecular, and periosteum.
What bones are produces by endochondral ossification?
Most bones of the body: bones of limbs, vertebrae, ribs, sternum, scapula, and pelvic girdle.
What kind of cells does periosteum have?
Bone-forming and bone-destroying cells.
What does epiphyseal plate serve as?
Growth plate
What is metaphysis?
Transitional zone on each side of the epiphyseal plate, where cartilage is replaced by bone.
What is interstitial growth?
Cartilage growth from within.
When is cartilage of epiphyseal plate depleted?
By late teens, early twenties.
The site of original epiphyseal plate becomes what?
The epiphyseal line
What is appositional growth? What does it aid in?
Deposition of new tissue at the bone surface. This aids in bone widening and thickening.
Bone widening and thickening (appositional growth) occurs by what process?
Intramembranous ossification at the bone surface
How much of the skeleton is replaced every year through bone remodeling?
10%
What is the function of bone remodeling?
Repairs microfractures, releases minerals into blood, reshapes bones in response to use and disuse.
What is Wolf’s law of bone?
The architecture of bone is determined by the mechanical stress placed on it.
What cells are function in bone remodeling?
Osteoblasts and osteoclasts
There needs to be a balance between bone deposition and bone destruction. So, there must be a balance between what 2 things?
Osteoblasts and osteoclasts
The bone is a store house for what?
Calcium
What is mineral deposition (mineralization)?
The crystallization process in which calcium, phosphate, and other ions are taken from blood and deposited in bone.
When does endochondral ossification begin and end?
It starts around the 6th week of intrauterine life and continues into a person’s 20’s.
What does the epiphyseal plate consist of?
Hyaline cartilage in the middle, with transitional zone on each side where cartilage is being replaced by bone.
What type of bone is the epiphyseal line?
Spongy bone
What does it mean when all of the epiphyses have closed in the lower limbs?
The person cannot grow any taller.
Bone elongation in the lower limbs causes…
A person to grow in height.
Bone elongation in the upper limbs causes…
The bones to grow proportionally.
What do osteoblasts produce during mineralization?
Osteoblasts produce collagen fibers that spiral in length of the osteon; fibers become encrusted with minerals.
What is mineral resorption?
Process of dissolving bone; releases minerals into blood.
What cells perform mineral resorption?
Osteoclasts
Where is mineral resorption performed at by osteoclasts?
At the ruffled border.
What is the normal calcium concentration in blood plasma?
9.2-10.4 mg/dl
What is hypocalcemia?
Calcium deficiency; when the blood calcium goes below 9.2 mg/dl
What happens in hypocalcemia?
There’s a change in meme rate potential which causes excessive excitability of the nervous system and tetany (muscle spasms).
What gland aids in reversing hypocalcemia?
Parathyroid gland
What does the parathyroid gland do to reverse hypocalcemia?
It releases a hormone called parathyroid hormone. This hormone stimulates the osteoclasts to destroy the bone to release calcium into the blood.
What organ does the parathyroid hormone increase calcium resorption by?
Kidneys
What organ does the parathyroid hormone increase calcium absorption by?
Intestines
What is hypercalcemia?
Calcium excess; when the blood calcium goes above 10.4 mg/dl
What happens in hypercalcemia?
It makes ion channels less responsive which causes nerve and muscle cells to be less excitable than normal.
Which is more common, hypocalcemia or hypercalcemia?
Hypocalcemia
What does calcium homeostasis depend on?
A balance between dietary intake, urinary and fecal losses, and exchanges between osseous tissue.
What 3 hormones is calcium homeostasis regulated by?
Calcitriol, calcitonin, and parathyroid hormone.
What is calcitriol?
It’s a hormone. Its the most active form of vitamin D produced by actions of the skin, liver, and kidneys.
What is the main function of calcitriol?
To increase the blood calcium.
What 3 ways does calcitriol act to raise blood calcium?
- Increases calcium absorption by small intestine.
- Increases calcium resorption from skeleton.
- It weakly promotes kidney reabsorption of calcium ions so less lost in urine.
What is calcitriol also necessary for?
Bone deposition by helping provide adequate calcium and phosphate.
What does inadequate calcitriol result in for children and adults?
It results in abnormal softness of bones. Called rickets in children and osteomalacia in adults.
What is rickets?
Abnormal softness of bones before bones have fused.
What is osteomalacia?
Softness of bones after bones have fused.
What is calcitonin?
It is a hormone that C-cells in the thyroid gland make and release to help regulate calcium levels in blood.
What 2 ways does calcitonin lowers blood concentration?
Osteoclast inhibition and osteoclasts stimulation.
What is osteoclast inhibition?
Inhibits osteoblasts thereby reducing bone resorption.
What is osteoclast stimulation?
Stimulates osteoclasts to deposit calcium into bone.
What is the normal plasma phosphate concentration?
3.5 to 4.0 mg/dl
What raises phosphate levels? By doing what?
Calcitriol, by promoting its absorption by the small intestine.
What lowers the blood phosphate levels? By doing what?
P T H (parathyroid hormone), by promoting its urinary excretion.
How many bones does the typical adult have?
206
How many bones in the axial skeleton and how many n=bone in the appendicular skeleton of an adult?
80 bones in the axial skeleton, 126 bones in the appendicular skeleton.
What is the difference between the male pelvic girdle and the woman pelvic girdle?
The male pelvic is heavier and thicker. The women pelvic is wider and shallower.
What are sesamoid bones?
Bones that form within the tendons (e.g., patella).
What are wormian bones?
Extra bones that develop in skull suture lines.
Why does the number of bones decrease from birth to adulthood?
Because of fusion of some bones.
What is a joint (articulation)?
Any point where 2 bones meet.
Why are joints needed?
They give mobility to the skeletal system.
What are joint classified by?
Structure and function
The joint structure classification is determined by what?
- What materials bind them together.
- Joint cavity (is there a space between the bones)
The joint function classification is determined by what?
Movement
What is arthrology?
The science of joint structure, function, and dysfunction.
What is kinesiology?
The study of musculoskeletal movement.
What is the structural classification of fibrous joints?
Fibrous membrane in between the bones.
No joint cavity (no space between the bones).
What are the 3 joint structural classifications?
Fibrous joints, cartilaginous, and synovial.
What is the structural classification of cartilaginous?
Hyaline or fibrocartilage in between the bones.
No joint cavity (no space between the bones).
What is the structural classification of synovial joints?
Synovial membrane in between the bones.
Has a joint cavity (has space between the bones).
What are the 3 movement classifications in joints?
Synarthrotic, amphiarthrotic, and diarthrotic.
What does synarthrotic mean?
No movement
What is an example of a synarthrotic joint?
A fibrous joint
What does amphiarthrotic mean?
No movement
What is an example of an amphiarthrotic joint?
A cartilaginous joint
What does diarthrotic mean?
Has movement
What is a fibrous joint?
Adjacent bones are bound by collagen fibers that emerge from one bone and penetrates into the other.
What are 3 kinds of fibrous joints?
Sutures, gomphoses, and syndemoses.
Where are sutures found?
Only in the skull
Where are gomphoses found?
In the mouth
Where are syndemoses found?
Found in between the ulna and radius, and between the tibia and fibula.
What is a cartilaginous joint?
2 bones that are lined by cartilage.
What are 2 types of cartilage bones?
Synchondroses and sympheses
What is a synchondrosis?
Bones joined by hyaline cartilage.
What are examples of synchondrosis joints?
Temporary joint between epiphysis and diaphysis of a long bone in a child. First rib attachment to the sternum.
What is a symphysis joint?
2 bones joined by fibrocartilage
What are examples of a symphysis joint?
Pubic symphysis joint, bodies of vertebrae joined by intervertebral discs.
What is a synovial joint?
Joint in which 2 bones are separated by a joint cavity.
What is the most common and most widespread joint?
Synovial joint
All synovial joints are highly __________ and highly ________.
Vascularized, innervated
What do synovial joints need?
Blood
What does the synovial membrane make?
It makes synovial fluid from blood vessels.
What is the general structure of synovial joints?
- Articular cartilage
- Joint cavity
- Synovial fluid
- Joint capsule
- Articular disc
- Meniscus
What is articular cartilage?
A layer of hyaline cartilage covering the facing surfaces of 2 bones. It’s usually 2-3 mm thick.
Where is articular cartilage found?
Found on the ends of bones.
What is the function of articular cartilage?
Reduces friction between bones.
What does an articular joint cavity do?
Separates articular surfaces.
What is synovial fluid?
Slippery lubricant in joint cavity.
What is a joint (articular) capsule?
Connective tissue that encloses the cavity and retains the fluid.
What are the 2 layers of a joint capsule?
Outer fibrous capsule and inner cellular synovial membrane.
What is the outer fibrous capsule of a joint capsule made up of?
Dense irregular connective tissue
The outer fibrous capsule is continuous with…
the periosteum of adjoining bones.
What is the inner cellular synovial membrane of a joint capsule made up of?
Areolar connective tissue with some elastic fibers.
What is the inner synovial membrane of a joint capsule?
It is composed of mainly fibroblast-like cells that secrete synovial fluid and macrophages that remove debris from the joint cavity.
What are the accessory structures associated with synovial joints?
Tendons, ligaments, bursa, and tendon sheaths.
What are ligaments in synovial joints? What are they needed for?
The thickened part of the fibrous capsule. They are needed to reinforce the joint.
What is a bursa?
An isolated pocket of synovial fluid, lined by synovial membrane.
What is a tendon (synovial) sheath?
An elongated bursa wrapped around a tendon.
What are synovial joints based on?
They’re based on the shape of the articulating surfaces (bone ends).
What are the 6 different types of synovial joints?
Planar joints, pivot joints, hinge joints, condyloid joints, saddle joints, and ball & socket.
What is a planar joint?
The ends of the bones are plane (flat).
What is the movement of planar joints?
Gliding
What are pivot joints?
The head of one bone fits into a sleeve of another.
What is an example of a pivot joint?
Radius and ulna, C1 and C2
What is a hinge joint?
It’s a monaxial joint, moving freely in one plane, with very little movement in any other, like a door hinge.
What is an example of a hinge joint?
Elbow, knee
What is a condyloid joint?
These joints have an oval convex surface on one bone that fits into a complimentary-shaped depression on the other.
What is an example of a condyloid joint?
Metacarpal phalanges joint of 2 to 5 digits.
What is a saddle joint?
Both bones have a saddle-shaped surface. One surface is concave (front-to-rear curvature) and one surface is convex (left-to-right curvature).
What is an example of a saddle joint?
Joint between the first metacarpal and the trapezium.
What is a ball and socket joint?
One bone has a smooth head that fits into a cuplike socket on the other.
What is an example of a ball and sock joint?
Head of the humerus, glenoid cavity of scapula.
What are movements of synovial joints classified as?
Gliding movements, rotational movements, Angular movements, and special movements.
What is an example of a gliding movement?
Waving
What are the 2 rotational movements?
Lateral rotation - away from the midline
Medial rotation - toward the midline
What are the 5 types of angular movements?
- Flexion - small angle created between bones
- Extension - large angle created between bones
- Adduction - away from the midline
- Abduction - bringing it closer together
- Circumduction - doing the 4 together in this order: flexion, adduction, extension, abduction. * Like drawing a circle in space.
What are the 11 types of special movements?
- Protraction - pulling forward
- Retraction - taking back
- Elevation - lifting up
- Depression - going down
- Supination - 2 bones are parallel facing up
- Pronation - 2 bones are parallel facing down
- Opposition - thumb touching the tip of the other 4 fingers
- Inversion - inward
- Eversion - outward
- Plantar flexion - curling your toes inward
- Doriflexion - fan your toes upward
What 4 types of special joint movements only happen in the feet?
Innversion, eversion, plantar flexion and dorsiflexion.
A fibrous joint is also called…
a synarthrosis
What are sutures?
Immobile fibrous joints that closely bind the bones of the skull to each other.
What is an example of a suture?
Squamosal, temporal, lambdoidal
What is a gomphoses?
The attachment of a tooth to its socket
What are syndemoses?
A fibrous joint at which 2 bones are bound by relatively long collagenous fibers.
What fibrous joint has the most mobility?
Syndemoses
What is interosseous membrane?
A thick, dense fibrous sheet of connective tissue that spans the space between 2 bones forming a type of syndemosis joint.
Where is interosseous membrane found?
Found between the shafts of the radius and ulna.
A cartilaginous joint is also called…
Amphiarthrosis
The other 11 ribs are attached to the sternum by…
Synovial joints
A synovial joint is also called…
Diarthrosis
What is an example of a synovial joint?
Elbow, knee or knuckle
Synovial fluid has a slippery texture similar to…
Raw egg whites
What is the function of synovial fluid?
It nourishes the articular cartilages, removes their wastes, and makes movements at synovial joints almost friction-free.
Where are tendon sheaths found?
In the hand and foot
What are planar joints found?
Between the carpal bones of the wrists, the tarsal bones of the ankle, and the articular processes of the vertebrae.
What are the functions of a bursa?
Cushion muscles, help tendons slide more easily over the joints, and sometimes enhance the mechanical effect of a muscle.
What is the function of a tendon sheath?
They enable tendons to move back and forth freely in tight spaces.
What are the 6 functions of muscles?
- Movement
- Stability
- Control of body passages and openings
- Thermogenesis
- Hormone secretion
- Glycemic control
What is the movement function of muscles?
Muscles enable us to move from place to place and to move individual body parts.
They move body contents in the course of breathing, blood circulation, feeding and digestion, urination, and childbirth; and they serve various roles in communication – speech, writing, facial expression, and other body language.
What is the stability function of muscles?
Muscles maintain posture by preventing unwanted movements.
Some are called antigravity muscles because, at least part of the time, they resist the pull of gravity and prevent us from falling or slumping over. Many muscles also stabilize the joints by maintaining tension on tendons and bones.
What is the control of body passages and openings in muscles?
Muscles encircling the mouth serve not only for speech but also for food intake and retention of food while chewing. In the eyelid and pupil, they regulate the admission of light to the eye. Internal muscle rings control the movement of food, bile, blood, and other materials within the body. Muscles encircling the urethra and anus control the elimination of waste. (Some of these muscles are called sphincters, but not all).
What is the thermogenesis function of muscles?
The skeletal muscles produce 20% to 30% of the body’s heat at rest and up to 85% during exercise.
This body heat is vital to the functioning of enzymes and therefore to all metabolism. When it is lacking, people die of hypothermia.
What is the hormone secretion function of muscles?
Exercised muscles secrete hormones (myokines) that stimulate glucose synthesis by the liver and breakdown of visceral (body-cavity) fat.
What is the glycemic control function of muscles?
The regulation of blood glucose concentration within its normal range.
The skeletal muscles absorb, store, and use a large share of one’s glucose and play a highly significant role in stabilizing its blood concentration. In old age, in obesity, and when muscles become deconditioned and weakened, people suffer and increased risk of type 2 diabetes mellitus because of the decline in this glucose-buffering function.
What is peristalsis?
How food is moved through the body from the esophagus to the anus.
Peristalsis in the digestive tract begins in the esophagus. After food is swallowed, it is moved down the esophagus by peristalsis. The muscles in the stomach, small intestine, and large intestine continue the process. Food is further digested and broken down as it moves through the digestive tract, aided by digestive juices that are added along the way. Bile, which is an important part of the digestive process, is produced in the gallbladder and is moved from the gallbladder into the duodenum (a section of the small intestine) via peristalsis. At the end of its journey through the body via peristalsis, the digested food is excreted through the anus as stool.
What is the belly (body) of the muscle?
The “belly” of the muscle is typically the largest or thickest portion of the muscle.
What is the origin of the muscle?
The place where the muscle starts; usually stationary.
What is the insertion of the muscle?
The place where the muscle ends. Moves towards the origin when the muscle contracts; this is called actin.
What is actin? What does it do?
A contractile protein. It does the work of contraction along with myosin.
What is muscle electrical excitability?
Responsiveness; they respond to electrical signals.
What is muscle contractibility?
Muscle fibers shorten in length when contracted.
What is muscle extensibility?
Capable of being stretched between contractions.
What is muscle elasticity?
Muscle returns to its original rest length after being stretched.
What is epimysium?
A connective tissue that covers the entire skeletal muscle.
What is perimysium?
A connective tissue that bundles muscle fibers into fascicles.
What is endomysium?
A connective tissue that surrounds each muscle fiber.
What is a tendon?
A strip of collagenous tissue attaching muscle to bone.
What is a tendon sheath?
An elongated cylindrical bursa wrapped around a tendon; abundant in hand and foot
What is sarcolemma?
The plasma membrane of a muscle fiber.
What are myofibrils?
Rod-like long protein cords occupying ¾ of the sarcoplasm.
What drives muscle contraction and relaxation?
Myofibrils
What are myofibrils composed of?
Muscle filaments or myofilaments.
What are transverse T tubules?
Tubular infoldings of the sarcolemma which penetrate through the cell.
What is sarcoplasm?
The cytoplasm of a muscle fiber.
What is sarcoplasmic reticulum (SR)?
Smooth endoplasmic reticulum that forms a network around each myofibril.
What are terminal cisterns?
They are dilated ends sacs that store and release calcium. Portions of the sarcoplasmic reticulum which are adjacent to the T tubules.
What are muscle fiber nuclei?
Muscle fibers have numerous sausage-shaped nuclei pressed against the inside of the sarcolemma.
What are mitochondria in the muscle?
Mitochondria convert nutrients into the molecule ATP, which stores energy.
Muscle has a high demand for ATP and therefore possesses an exceptionally large number of mitochondria wedged in between the myofibrils. Mitochondria near the sarcolemma have the typical bean shape seen in many other cells, but deep inside the muscle fiber, they form a more dynamic, ever-changing tubular network influenced by exercise.
In what order are skeletal muscles organized?
- Skeletal muscle
- Fasciculus
- Fiber
- Myofibrils
- Myofilaments
- Thick myofilaments called myosin, Thin myofilaments called actin.
What are skeletal muscles?
Skeletal muscles are voluntary, striated muscle usually attached to bones.
What are fascicles?
Bundles of muscle fibers.
How many fascicles make up 1 muscle fiber?
100’s to 1000’s of bundles make up 1 muscle fiber
What are muscle fibers?
Skeletal muscle cells are called fibers because they are long and cylindrical.
What are muscle fibers filled with?
Rod-like bands called striations
How much of the muscle fiber is filled with striations?
3/4 of the muscle fiber
What is the sarcomere?
A segment from Z disc to Z disc; functional contractile unit of muscle fiber.
What is the functional contractile unit of muscle fiber?
Sarcomere
What is the structural and functional unit of a skeletal muscle?
Sarcomere
What are the 3 components of thin filaments?
They are composed of 3 different protein types: filament F actin, tropomyosin, and troponin.
What is the thickness of thin filaments?
8 nanometers
What do thin filaments look like?
Look like 2 strings of beads intertwined.
What is each string of beads in a thin filament called?
Filament F actin
What are thick filaments made of?
Made of several hundred myosin molecules.
What is the thickness of thick filaments?
16 nanometers
What are thick filaments?
A-band myofibrils.
How many myosin make up 1 thick filament?
300
What are the 5 structures of thin filaments?
- Actin
- Myosin-binding site
- Troponin
- Calcium-binding site
- Tropomyosin
What is the actin of thin filaments?
Fibrous f actin are 2 intertwined strands of globular (g) actin subunits, each with an active site that can bind to the head of a myosin molecule.
What is the myosin-binding site of thin filaments?
Each G actin has an active site that can bind to the head of a myosin molecule.
What is troponin of thin filaments?
Small calcium-binding protein on each tropomyosin molecule.
What is the calcium-binding site of thin filaments?
What is tropomyosin of thin filaments?
Each blocks 6 or 7 active sites on G actin subunits and prevents myosin from binding to them.
What does tropomyosin look like?
Looks like the string through a string of beads.
What are the 4 structures of thick filaments?
- Myosin
- Myosin heads
- ATP binding-site
- Myosin tails
What is myosin in thick filaments?
It’s a motor protein that has globular heads of ATPase that bind to actin molecules.
What does myosin look like?
One myosin molecule looks like 2 golf clubs: 2 chains intertwined to form a shaft-like tail and a double globular head.
What are the myosin heads?
The heads can be found in either energized or non-energized forms. The heads become energized through the binding and hydrolysis of ATP, which includes conformational change, energizing it and preparing it for muscle contraction.
What must myosin heads have bound to them?
An ATP molecule
What is the ATP binding site of thick filaments?
Myosin ATPase, an enzyme in the head, hydrolyzes this ATP into ADP and phosphate. The energy released by this process activates the head, which “cocks” into an extended, high-energy position.
What are myosin tails?
What are troponin and tropomyosin called? Why?
Regulatory proteins because, together, they act like a switch to determine when the fiber can contract and when it can’t.
What are striations?
Alternating A-bands (dark) and I-bands (light).
What is myology?
The study of muscles
What are the 3 types of muscle?
Smooth, skeletal, and cardiac
What does sarco- mean?
Flesh
What does myo- or mys- mean?
Little mouse
How many skeletal muscles are there in the human body?
669
All skeletal muscles are attached to…
The skeleton
What 4 things does each skeletal muscle have?
- Own blood supply
- Own nerve supply
- Place where they start
- Place where they end
Why are transverse T tubules needed?
So electrical signals can pass through the muscle.
Skeletal muscle is also called…
Striated
Many nuclei are found below the sarcoplasm. So skeletal muscles are…
Multinucleated
What is the glycogen component of muscle fiber?
Carbohydrate stored to provide energy for exercise.
What is the myoglobin component of muscle fiber?
Red pigment, provides some oxygen needed for muscle activity.
What is an A-band?
A dark band
Where is the darkest part of an A-band?
Where thick filaments overlap a hexagonal array of thin filaments
What is an H-band? Where are they located?
The middle of an A-band. It’s not as dark. In thick filaments only.
What is an M-band?
A dark, transverse protein in the middle of an H-band
What is an I-band?
A light band
What is a Z disc/Z line?
Protein complex that provides anchorage for thin filaments and elastic filaments.
What is the distance between the 2 Z disc/Z lines?
2 micrometers
What is aponeurosis?
A broad, flat sheet of tendon-like material that anchors a muscle or connects it with the part that the muscle moves.
What is a triad??
It is a 3 element complex consisting of 2 terminal cisterns and a T tubule in the middle.
Where are triads located?
At the junction of the A band and I band.
What is the agonist (prime mover)?
The muscle that produces most of the forces during a particular joint action.
What is the antagonist?
The muscle that opposes the prime mover.
In some cases what does the antagonist do?
It relaxes to give the prime mover almost complete control over an action.
More often, what does the antagonist do?
The antagonist maintains some tension on a joint and thus limits the speed or range of the prime mover, preventing excess movement, joint injury or inappropriate actions.
What is the synergist?
The muscle that aids the prime mover. Two or more synergists acting on a joint can produce more power than a single larger muscle.
What is the structure of smooth muscle concerning intercalated discs?
No intercalated disc.
Where is smooth muscle located?
Walls of viscera (stomach, intestines, uterus, and urinary bladder), and blood vessels, iris of eye, and arrector muscle of hair follicles.
What is the function of smooth muscle?
Propels the contents of an organ, such as driving food through the digestive tract, voiding urine and feces, and expelling infant in childbirth. By dilating or constricting the blood vessels and airways, it can modify the speed of air and blood flow, maintain blood pressure, and reroute blood from one pathway to another.
What type of control is smooth muscle?
Involuntary
Smooth muscle nerve supply is…
Autonomic
What is the structure of cardiac muscle concerning intercalated discs?
Have intercalated discs.
Explain intercalated discs in cardiac muscle.
Cardiomyocytes branch slightly so each is joined end to end with several others. These intercellular connections are called intercalated discs. Gap junctions are present in the intercalated discs.
Where is cardiac muscle located?
The heart
What is the function of cardiac muscle?
- Pumps blood
- Must contract with regular rhythm.
- Must function in sleep and wakefulness, without fail or need of conscious attention.
- Must be highly resistant to fatigue.
- The cardiomyocytes of a given heart chamber must contract in unison so the chamber can effectively expel blood.
- Each contraction must last long enough to expel blood.
What type of control is cardiac muscle?
Involuntary
Cardiac muscle nerve supply is…
Autonomic
What is the structure of skeletal muscle concerning intercalated discs?
No intercalated discs.
Where are skeletal muscles located?
Associated with the skeletal system.
What is the function of skeletal muscle?
Contract to produce movement, sustain body posture and position, maintain body temp, store nutrients, and stabilize joints.
What type of control is skeletal muscle?
Voluntary
What are the contractile proteins?
Myosin and actin
What is the function of contractile proteins?
They do the work of shortening the muscle fiber.
What are the regulatory proteins?
Tropomyosin and troponin.
What is the function of regulatory proteins?
Together, tropomyosin and troponin act like a switch to determine when the fiber can contract and when it can’t.
What are the structural proteins?
Myosin, actin, tropomyosin, and troponin.
What do the 4 structural proteins form?
They form the foundation of the basic contractile unit called the sarcomere.
What is ATP hydrolysis?
A chemical reaction where a phosphate bond is broken by water, thereby releasing energy.
What does ATP hydrolysis produce?
ADP (adenosine diphosphate), Pi (inorganic phosphate), and energy.
What is the function attachment of myosin to actin to form cross bridges?
The globular heads of myosin containing ADP and Pi bind with actin, forming cross-bridges between the myosin and actin filaments.
What is the power stroke?
Myosin releases ADP and Pi, and flexes into a bend, low-energy position, tugging the actin along with it towards the Z line.
The myosin head remains bound to actin until…
it binds with a new ATP.
What is the function detachment of myosin from actin?
The binding of a new ATP to myosin destabilizes the myosin-actin bond, breaking the cross-bridge. ATP is reformed, and it detaches the myosin head from the actin.
What are somatic motor neurons?
Nerve cells whose cell bodies are in the brainstem and spinal cord.
What do the somatic motor neurons serve?
They serve skeletal muscles.
What are synaptic vesicles?
Spheroidal organelles in an axon terminal containing acetylcholine.
Acetylcholine is an example of a…
Neurotransmitter
What is the axon terminal?
The site of synaptic vesicles and neurotransmitter release; the swollen tip at the distal end of an axon.
What are neurotransmitters?
The body’s chemical messengers.
What is the synaptic end bulb (knob)?
The tip of the axon enlarges and becomes known as the synaptic end bulb. It is towards the end of the axon terminal, closest to the muscle fiber.
What is a muscle fiber?
One skeletal muscle cell; a myofiber.
What is a motor end plate?
The point where a nerve fiber meets a target cell that is a muscle fiber.
What is a motor end plate also called?
Neuromuscular junction (NMJ)
What are acetylcholine receptors?
Proteins incorporated in the sarcolemma across from the axon terminals.
What is the synaptic cleft?
A narrow space between an axon terminal and the membrane of the postsynaptic cell.
Where does a neurotransmitter diffuse?
Across a synaptic cleft.
What is the role of creatine phosphate in regards to production of ATP in muscle fibers?
Aids in rapidly generating ATP.
What is the role of myoglobin in regards to production of ATP in muscle fibers?
To release oxygen to produce ATP.
What is anaerobic cellular respiration?
A type of respiration where oxygen is not used.
What does anaerobic cellular respiration allow a cell to do?
It enables a cell to produce ATP without the need for oxygen, but the ATP yield is very limited.
What does the process of anaerobic cellular respiration generate?
A toxic by-product called lactate (lactic acid).
What is aerobic cellular respiration?
A type of respiration that produces far more ATP and no lactate.
What does aerobic cellular respiration require?
A continual supply of oxygen.
What are the 2 contributing factors to muscle fatigue for high intensity, short-duration exercise?
- Potassium accumulation
- ADP/Pi accumulation.
What is muscle fatigue?
The progressive weakness and loss of contractility that results from prolonged used of the muscles.
What are the 3 contributing factors to muscle fatigue for low intensity, long-duration exercise?
- Fuel depletion
- Electrolyte loss
- Central fatigue
What is lactic acid?
Fuel for your cells during exercise.
How is lactic acid formed and accumulated?
Under conditions of high energy demand, rapid fluctuations of the energy requirement and insufficient supply of oxygen.
What is a motor unit?
One motor neuron and all of the skeletal muscle fibers innervated by it.
What are small motor units for?
When fine control is needed.
What are large motor units for?
When strength is more important than fine control.
What is a twitch contraction?
When a muscle is directly stimulated with an electrode, it exhibits a quick cycle of contraction and relaxation.
What is the latent period of a muscle twitch?
The interval between a stimulus and response, especially in the action of a nerve and muscle cell.
What is the contraction period of a muscle twitch?
Once the elastic components are taut, the muscle begins to produce external tension and move a resisting object, or load, such as a bone or body limb.
What is the relaxation period of a muscle twitch?
The sarcoplasmic reticulum begins to quickly absorb Ca2+ even before the muscle develops maximal force. As the Ca2+ levels fall, myosin releases the thin filaments and muscle tension declines.
What is the refractory period in muscle fiber contraction?
A period of time after a nerve or muscle cell has responded to a stimulus in which it can’t be re-excited by a threshold stimulus.
What are the 2 phases of the refractory period in muscle fiber contraction?
Absolute refractory period and relative refractory period.
What is the absolute refractory period?
In which no stimulus of any strength will trigger a new action potential.
What is the relative refractory period?
In which it is possible to trigger a new action potential, but only with an unusually strong stimulus.
What is wave summation?
At higher stimulus frequencies, each new stimulus arrives before the previous one and generates higher tension. This phenomenon goes by wave summation because it results from one wave of contraction added to another.
What is unfused (incomplete) tetanus?
Wave upon wave, each twitch reaches a higher level of tension than the one before, and the muscle relaxes only partially between stimuli. This effect produces a state of sustained fluttering contraction called incomplete tetanus.
What is fused (complete) tetanus?
In the lab, an isolated muscle can be stimulated at such high frequency that the twitches fuse into a single, nonfluctuating contraction called complete tetanus.
What is motor unit recruitment?
The process by which different motor units are activated to produce a given level and type of muscle contraction.
Motor unit recruitment is…
Part of the way the nervous system behaves naturally to produce varying muscle contractions.
What is muscle tone?
A state of continual, partial contraction of resting skeletal or smooth muscle.
What is the importance of muscle tone?
It maintains optimal sarcomere length and makes the muscles ideally ready for action.
What is isometric muscle contraction?
In which a muscle develops tension but doesn’t shorten.
What is isotonic muscle contraction?
In which muscle maintains tension while it lengthens, allowing a muscle to relax without going suddenly limp.
What is the length-tension relationship?
The tension generated by a muscle, and therefore the force of its contraction, depends on how stretched or contracted it was at the outset.
