Med 1001 Flashcards
1
Q
What is an organelle and what are the types of organelles?
A
the internal components of a cell which carry out specific metabolic tasks. there’s membranous and non membranous
2
Q
What are membranes within a cell usually made of and why is this material used?
A
phospholipids. they have a non polar tail and polar head so they are ampipathic, meaning they interact with both water and lipids.
3
Q
How are membranes generally formed?
A
phospholipids in solution will self associate, forming a bilayer where hydrophobic tail comes faces inwards and polar head faces outwards
4
Q
What is a vesicle?
A
A bubble which has a membrane formed from phospholipid bilayer, might have stuff in it
5
Q
What is the difference when we say a cell is anuclear or multinucleate?
A
Anuclear means no nucleus, multinucleate means multiple nuclei
6
Q
What is the function of the nucleus?
A
The nucleus stores our genes in the form of DNA within chromatin
7
Q
Where are ribosomes produced?
A
In the nucleus, there are nucleoli comprised of masses of DNA, RNA and/or proteins
8
Q
What is something that the nucleus shares with the mitochondria and describe it’s role in the nucleus’ operations
A
A double membrane
Regulates molecular traffic in and out of the nucleus (pores as well). For stuff to get out of the nucleus, there’s these nuclear pores which are dotted around the nucleus which are formed by rings of protein. The outer nuclear membrane ends up becoming the rough endoplasmic reticulum.
9
Q
What is the purpose of ribosomes?
A
Production of proteins
10
Q
Where can ribosomes be found?
A
Floating in the cytoplasm, on membranes (RER, nuclear membrane) or within other organelles (nucleus, mitochondria
11
Q
How do ribosomes achieve their purpose
A
They ‘read’ coded genetic messages in the form of messenger RNA, and start building amino acids in a specific order to produce a protein. This is called translation. The proteins are then released in vesicles
12
Q
What is the endoplasmic reticulum?
A
A system of channels covered by a membrane
13
Q
What is the difference between rough and smooth endoplasmic reticulum structurally?
A
Rough ER has ribosomes on it, while smooth doesn’t
14
Q
What is the purpose of the rough endoplasmic reticulum?
A
Production of phospholipids and proteins for plasma membrane
Makes proteins via ribosomes
15
Q
What is the function of the smooth endoplasmic reticulum?
A
Synthesis fats, lipids and steroid hormones
Begins to detoxify alcohol and other drugs
In muscular cells, acts as a store of calcium
16
Q
What is the function of the Golgi apparatus?
A
The golgi apparatus modifies proteins by attaching sugar or sulfate groups on proteins, making it more water soluble.
17
Q
What is endocytosis and what are the types of endocytosis?
A
When the cell takes stuff into it
Can be phagocytosis, when big stuff is taken in
Can be pinocytosis, when small stuff is taken in
18
Q
What is exocytosis and what forms can it take?
A
Stuff is taken out of the cell
Constitutive (stuff is just taken out almost randomly)
Regulated (there’s a structure and system to releasing)
19
Q
What is the cytoskeleton?
A
It’s a network of protein filaments which can grow and shrink to determine cell shape and size. It allows for exo and endocytosis
20
Q
What are the components of the cytoskeleton?
A
Microfilaments (made of actin) (smallest): Contribute to cell shape and movement.
Intermediate filaments: Provide mechanical strength, they hold up the cell
Microtubules (made of tubulin) (biggest): Help with intracellular transport, determine position of organelles and play role in cell shape and cell division
21
Q
How are vesicles transported around the cell?
A
motor proteins attach themselves to the protein filaments and the vesicle and move along the filaments when ATP attaches to it, dragging the vesicle with it
22
Q
What is the function of a lysosome and peroxisome?
A
To protect the cell from foreign bodies and/or defective bodies
23
Q
How do peroxisomes achieve their purpose?
A
- They use hydrogen peroxide to oxidize them, breaking them down
- They break down toxins such as alcohol and free radicals
- They also break down fatty acids into acetyl groups to be used in mitochondria
- They have a membrane to prevent hydrogen peroxide from getting out
24
Q
How do lysosomes carry out their function?
A
Lysosomes are membrane bound and contain enzymes which are used to break down organelles, proteins, nucleic acids etc.
As enzymes are used, only work on specific things as specific reaction
25
What are proteasomes and what is their function?
Proteasomes are membrane bound organelles which recycle proteins.
- Cell marks damaged or old protein with ubiquitin
- Proteasome takes these marked proteins and breaks them down to amino acids
26
What are autophagosomes and what is their function? Also what's unique about them?
Autophagosomes are membrane bound organelles which recycle other organelles.
- They form a membrane around an organelle, surrounding it and they fuse with a lysosome where using the enzymes, the organelle is broken down into usable parts for the cell
- What's special about them is that they pop up when needed, don't exist all the time
27
What is the function of the mitochondria?
- Produce ATP or energy for the cell
- Respiration occurs within the mitochondria too
28
Describe the overall structure of the mitochondria
It has a double membrane
- Outer membrane is for security
- Inner membrane has folds called cristae
- The space between the cristae is called the matrix
- Within the matrix is a bunch of stuff like ribosomes and enzymes used for ATP production
- Also, ATP synthesis happens at sites in the mitochondria called ATP synthases
29
What is the difference between prokaryote cells and eukaryote cells?
- Prokaryotes don’t have a nucleus and don’t have membrane bound organelles
- Eukaryotes have a nucleus and membrane bound organelles
30
What size is a human cell?
30 to 50 microns (30 to 50*10^-6
31
Why is the size of a cell so important for survival?
- Cells float around in extracellular fluid
- Any nutrients a cell needs come from this ECF (fats, sugars etc.)
- To maximise how much stuff it takes in, we want to maximise surface area
- As you increase the size of a cell, it’s volume increases and it needs more nutrients hence a larger surface area
- However, as you increase the volume of something, it’s surface area decreases, so the surface area to volume ratio decreases
- This means the cell cannot function properly past a certain size
32
Why is SA:V ratio important in regards to cells?
- If the volume increases, so does the amount of cytoplasm hence the cell needs more nutrients
- A larger surface area means the cell can absorb more nutrients at a greater rate
- We need to maintain this surface area to allow the exchange of nutrients, ions, waste and gases
33
When cells differentiate, why is it known as a trade off?
- The cells which they differentiate from can’t perform super specific and complex tasks but they can remain alive on their own, they can perform metabolic processes on their own
- However, specialised cells such as cardiac cells will die if we put them on a dish
- We gain skills but we also lose things like being able to live on our on
- The specialised cells rely on the whole organism to keep them alive
34
What are the 4 main types of tissues?
- Muscular
- Nervous
- Epithelial
- Connective
35
What is the function of nervous tissue?
It conducts electrical impulses and is the cell which forms the control system of our body
36
What is the function of muscle tissue?
- Made of contractile cells, it allows your body to move
- These contractile cells are responsible for movement, pumping blood and changing size
37
What is the function of epithelial tissue?
- A lining tissue that line all the organs in your body
- It allows for secretion, absorption, filtration, protection and contributes to stretchiness
38
What is the purpose of connective tissue?
Anything that isn't the other 3 tissues is considered connective. Connects shit together
39
What are the two further types of cells which comprise nervous tissue?
Neurons (detect stimuli and transmit messages) and neuroglia (protect and assist neurons)
40
What are the types of muscl cells?
Smooth, skeletal and cardiac
41
When we talk about epithelial tissue, there’s 3 words we use (the third being epithelium) (there’s one exception):
What can the first word be and what does it describe?
- It can be simple, pseudostratified or stratified
- Simple means that there’s only one layer of cells
- Stratified means that there are two or more layers of cells
- Pseudostratified means it’s 1 layer but the cells are squished so it looks like there’s more than one layer
(refers to how cells are layered)
42
When we talk about epithelial tissue, there’s 3 words we use (the third being epithelium) (there’s one exception):
What can the second word be and what does it describe?
- Squamous, cuboidal, columnar
- Squamous means the cells are squished thin
- Cuboidal means cells are like cubes
- Columnar means the cells are arranged like columns
(refers to the actual shape of the cell)
43
Summarise the differences in function between all the different types of epithelium
- The thinner, squamous cells are used for exchanging nutrients and materials
- Cuboidal and columnar are more useful for absorption and secretion
- Stratified epithila is more for protection and providing stretchiness
- Simple is more for exchange of materials
44
What is transitional epithelium?
- Lots of small epithelium cells stacked on top of each other
- Mainly used for stretchiness
45
What makes connective tissue unique from the other tissues?
There’s not actually many cells, there’s a lot of open space which is filled with an extracellular matrix
46
What can comprise ECM and how can this be explain the difference between bones and red blood cells despite both being connective tissue?
- ECM can be comprised of fibres or ground substance
- The fibres can contain collagen which is strong and elastin which is stretchy
- Ground substance contains stuff like glycoproteins (remember carbs and protein) which make it a kind of gel and it contains GAGs
- All connective tissue types contain both fibres and ground substance in varying amounts
- For example in blood, there’s more ground substance than fibres (especially collagen)
- Meanwhile in bone, it’s mainly collagen with calcium salt
47
Examples of connective tissue
- Blood
- Fat
- Cartilage
- Bone
- Fibrous connective tissue
48
What are the three ways cells are held together?
- Tight junctions or occluding junctions
- Desmosomes or adhaerans junctions
- Gap Junctions or communicating junctions
49
Describe what the function and characteristics of an occluding junction are
- A tight junction seals the small gaps between cells and forces substances to go through cells rather than the spaces between them
- Note: They are tight (water tight, don’t let things through) BUT THEY ARE NOT STRONG
- This is because adhesive proteins known as claudins attach only to the plasma membrane which is a weak connection
50
Describe the function and characteristics of an adhaeran junction
- A desmosome is a super strong connection between two cells which hold them together
- They are strong because protein known as cadherins attach to the intermediate filaments in the other cells cytoskeleton
51
Describe the function and characteristics of a communicating junction (in terms of structure)
- Gap junctions allows small ions, molecules and nutrients to pass through from one cell to another
- It also allows for direct communication between two cells
- Between two cells exist connexons
- Connexons are rings of proteins that have a pore or hole in the middle of them which allows stuff to pass through
- Connexons exist on the membrane of two cells which are next to each other, adjacent
- Can be located in cardiac and smooth muscle
52
What are the basic components of cell communication (ignore gap junctions)?
- A signalling cell which sends a cell known as a ligand
- A receiving cell which receives the ligand at a receiver or receptor
53
What are the different ways that cells talk to each other?
- Direct:
- Juxtacrine
- Gap Junctions
- Via ECF
- Autocrine
- Paracrine
- Endocrine
- Neuronal
54
Explain how gap junctions facilitate cell communication
- Direct form of cell communication
- Gap junctions allow communication between two cells in direct physical contact with each other
- The communicating junction connects two cytoplasms together and allows free passage of molecules and ions
- It can be found in the heart and some smooth muscle (this kind of communication)
55
Explain how juxtracrine cell communication occurs
- Direct form of cell communication
- On the signalling molecule there is a ligand component but it is directly connected to the receptor of a neighbouring cell
- Hence the ligand/signal never actually travels out of the cell, goes straight to the other cell
56
Explain what and how autocrine cell commucation occurs
- This is done via ECF
- It occurs when the cell (auto) signals to itself
- It occurs over very small distances (less than 20 microns)
57
Explain what and how paracrine cell communication is
- Occurs between cells not in phyical contact
- Signalling cell releases ligand into ECF and it acts on other cells which are close by
- Ligand attaches to receptor
58
Explain endocrine cell communication
- Acts over long distances
- Signalling cell dumps ligand into bloodstream where it keeps going until it finds a cell with a receptor capable of receiving the ligand
- As the bloodstream spans the whole body, the ligand will eventually reach the target cell
59
Explain how neuronal or neural communication happens
- Acts over long distances
- The ligand is transmitted over a neuron and it arrives at a very specific area of cells
60
What is the function of membranes?
Selectively permeable barrier
* Compartmentalization
* Scaffold for biochemical activities
* Can respond to external signals
* Intercellular interaction
* Energy transduction
* Transporting solutes
protection
61
What is transported across cell membranes?
- macromolecules
- small solutes (neutral and non polar molecules)
- polar and charged molecules/ions
62
Why do molecules actually move around and not just stay still?
- Molecules are constantly in random motion (brownian motion)
- according to second TMC law, systems tend to disorder, stuff wants to move away from each other
- So molecules will diffuse, from region of high conc. to low conc.
63
What governs if molecules diffuse (chemically)?
- The concentration gradient
- If there’s no difference in concentration between two regions, diffusion will not occur
64
How do other ions, molecules etc. affect concentration gradients?
- Other molecules do not affect the diffusion of another molecule
- However, if charge is involved stuff might happen
65
What is Fick’s Law of Diffusion?
- Allows us to calculate flux
- Flux is the number of molecules passing through a certain area in a given amount of time
- Flux is proportional (increases) as concentration gradient increases (the difference in concentration is higher) and is inversely proportional to the distance molecules have to travel
- Also, different molecules diffuse through different things at different rates
- So there’s diffusion co-efficient, which measure how easily diffusion occurs for that solute through that solution
66
What is required for diffusion to occur (structurally)?
- A permeable membrane
- If no permeability, absolutely no diffusion can occur
67
What kinds of molecules diffuse the fastest through membranes?
Small, non polar molecules (over our lipid bilayer)
68
What are the 5 factors which affect diffusion rate and how do they affect diffusion?
- As the concentration gradient increases, DR (diffusion rate) increases
- As surface area of membrane increases, DR increases
- Lipid solubility increases, DR increases
- Molecular weight increases, DR decreases
- Distance molecule has to travel or thickness membrane increases, DR decreases
69
What is the ionic composition of ECF vs ICF?
- Main cation in ECF: Na + , Main anion in ECF: Cl-
- Main cation in ICF: K+, main anion in ICF: PO4 (3-)
70
What is osmosis and how does it occur?
- The movement of water across a membrane
- Special because although water is small, it’s polar so DR is kind of low across a membrane
- So, cells have water channels called aquaporions
- These allow bidrectional diffusion (into and out of cell) of H2O
- Specific to water
- Increases the diffusion rate by more than 10x
71
What is osmolarity?
- We don’t measure the concentration of water
- We measure how much stuff is within the water compared to the amount of water present
- Water diffuses goes from a low osmolarity to high osmolarity
- Simply put: Lots of shit in little water
72
What is osmolarity of a typical cell’s cytoplasm?
- 300 MILLI OSMOLES PER LITRE
- 300 mOsmoles/L
73
What is tonicity and what are the 3 kinds of tonicity?
- Always assume cell is within some solution
- Hypotonic: The solution is hypotonic, water will flow into the cell as more shit in the cell compared to outside, solution has lower osmolarity
- Isotonic: The solution and cell have similar osmolarity
- Hypertonic: Solution has higher osmolarity, so water flows out from the cell
74
Compare and contrast osmolarity and tonicity and how they are related
- Osmolarity is a numerical measurement
- Tonicity is relative
- Sometimes if two substances are iso-osmolar (same osmolarity), they can be isotonic
- However other times, they may not be
- BECAUSE: You can have the same amount of solutes, but different solutes
- The solutes may diffuse which will lead to difference in osmolarity after
75
What are ways diffusion can occur in a cell? (what structures)
- Through the membrane
- Through channels and pores
76
What are the different membrane transport processes?
- Simple passive diffusion
- Protein carriers
- Diffusion through a carrier or port
- Diffusion through symport (same direction)
- Diffusion through antiport (opposite direction)
- Pumps
- A pump transports stuff
- This is a primary active transport as it uses ATP or energy
- Doesn’t need a concentration gradient like the others
Proteins + Pumps are carrier mediated but proteins still involve diffusion principles
77
Compare and contrast pores and channels
- They’re both filled with water
- They both increase the permeability of the cell
- They both are selective
- Pores have a region inside them where depending on shape, size, charge, they let stuff through
- Pores are always open however, the other end is open
- Channels are basically just pores but they have a gate that can be open and closed
- This means you can control the permeability of the cell
- Channel proteins are very specific
78
What are the ways a membrane channel’s gate can be controlled?
- Voltage gated
- Ligand gated, a ligand opens it up
- This ligand may open it from the inside of a cell or the outside
- Mechanically gated
79
Describe the rate of transport for simple diffusion processes graphically
- For simple diffusion across a membrane, through pores or channel proteins
- The higher the concentration gradient, the faster the diffusion will take place
- Rate of transport when a channel protein has closed gate is nothing remember, because the permeability is 0
- Rate of transportation is linear, with CG on x axis and flux on y axis
80
How do carriers or transporters help with bringing stuff in and out of cells?
- Carriers are open either to the inside of the cell or outside of the cell
- Specific stuff will come in, bind to the carrier and then the carrier opens itself to the other side, releasing the solute or thing
- This process is called facilitated diffusion because the energy for this still comes from a concentration gradient
- They are specific because only specific things can act on the binding site of the carrier
- They work equally well in both directions
81
Compare and contrast the rate of transport for carriers vs diffusion processes
- The rate of a carrier doesn’t increase linearly like diffusion processes as you increase the concentration gradient
- There is a saturation point because the carrier has a limited working speed, to open and close itself
- There’s also a fixed number of these carriers, so at some point just increasing the gradient won’t do anything
- Also the rate can be affected because the transport rate is dependent on:
- Temperature
- Competition for binding site
82
What are the types of carrier proteins?
- Uniporters
- Transport a single, specific solute from one side of the membrane to the other
- Co-transporters
- To transport one solute, you need another, different solute to be transported at the same time
- There are two types:
- Symporters: Where both solutes are transferred in the same direction
- Antiporters: Where both solutes are transferred in opposite directions
83
Why are co-transporters so unique and significant?
- They can use the concentration gradient of one solute to drive the transfer of another solute, effectively making it a good scavenger
- This is called secondary active transport
- We use the transport of one solute, to get the transport of another solute
- E.g: Sodium and glucose
84
How does a pump work in the membrane transport system
- Pumps use the chemical energy from the bonds in ATP to move molecules against the concentration gradient
- Carrier proteins can be used to pump the solute across
- Pumps are not diffusion
- Pumps can also be antiport or symport
85
Compare and contrast facilitated diffusion and active transport
- Facilitated diffusion used protein carriers
- Active transport uses pumps (which are ATPases that are also carriers)
- Both pumps and carriers are called transporters
- They both are a part of carrier mediated transport
86
What ‘makes’ vesicles?
- Coat proteins
- They pinch out a vesicle, like getting an ice cream scoop
- There’s 3 different ones for different parts of the cell from which the vesicle comes
- At the plasma membrane it’s done by clathrin
- At endoplasmic reticulum, it’s done by Coat Protein II or COPII
- At Golgi it’s done by Coat Protein I, COPI or clathrin as well
87
How do vesicles know what destination they have to go to?
- Proteins called RABS give the address for where a vesicle needs to go (golgi, membrane etc)
- Rabs bind to a motor protein, it goes along a microtubule to it’s destination
88
What is the function of SNARES in vesicle transport?
- Snares mediate fusion of a vesicle to the place it’s supposed to go (maybe it has to deliver a protein)
- There’s two types
- V-snares which attach to the vesicle
- T-snares which attach to the target
- Snares work like velcroid, they pull the vesicle in and the contents are exocytosed
89
What are the two distinct layers of our skin?
- Epidermis (outer layer), acts as a protective shield
- Dermis, makes up the bulk of skin and is superior (on top) of hypodermis
90
Describe the epidermis
- Avascular (no blood vessels)
- It’s a keratinised sheet of stratified epithelium, made of various melanocytes, dendritic cells and tactile cells in it’s deepest layers
91
What are the 4/5 layers of the epidermis?
- Stratum basale
- The deepest layer
- It has one row of active mitotic cells which begin to produce keratinocytes
- Sratum spinosum
- Second deepest layer
- Formed by several layers of keratinocytes which are unified by desmosomes
- Stratum granulosum
- Stratum lucidum (only in thick skin)
- Stratum corneum
92
How long does it take for skin cells to get from stratum basale to stratum corneum?
25 - 45 days
93
Describe the location and make up of the dermis
- Deep (below) to the epidermis
- Superficial (above) the hypodermis
- It’s made up of dense connective tissue (collagen fibers)
- Contains blood vessels, lymphatic vessels and nerves
- Connected to underlying deep fascia or bones by subcutaneous (beneath skin) tissue
94
Describe the hypodermis
- It’s deep to the dermis
- It’s mainly comprised of adipose tissue (fat store) which allows is it to shock absorb and insulate
- Anchors skin to underlying tissues, such as muscles
95
What are the kinds of skin markings which exist?
- Flexure lines
- Can be seen on your hand, bottom of your feet
- This is where the dermis tightly attaches to the underlying structure
- The skin at these points cannot slide easily, causing deep creases
- Striae
- Silvery-white scars
- Happen where extreme stretching has caused the dermis to tear
- Also called stretch marks
- Blister
- Happen from acute short term trauma
- It’s a pocket which forms between the epidermis and dermis and filled with fluid
96
List the skin appendages
- They are derivatives of the epidermis
- Hairs and hair follicles
- Nails
- Sweat glands
- Sebaceous (oil) glands
97
Describe hair and hair follicles (functions, general structure)
- Hair grows out of follicles
- The hair follicle penetrates to deeper part of epidermis for blood supply
- Smooth muscle called arrector pilli connect follicles to the superficial (upper) part of dermis
- Hair is made of dead keratinized cells of hard keratin (hair is hard keratin)
- Doesn’t grow on your palms, soles of your feet, lips, nipples, portions of external genetalia
- Protective Functions:
- Warns when insects are on skins (flies and mosquitoes)
- Protects from physical trauma (sliding)
- Helps to prvent heat loss
- protect us from Sunlight
98
Types of hair
- Vellus hair
- Pale, fine body hair of children and adult females
- Terminal hair
- Coarse, long hair of eyebrows and scalp
- At puberty
- Appear in pubic regions
- Face and neck of males
- Nutrition and hormones affect hair growth
- Follicles will cycle between active and regressive phases
99
What are the types of sweat glands?
Sweat Glands
- Eccrine and Apocrine
Sebaceous or oil Glands
100
Describe sweat glands
- On all skin surfaces except nipples and parts of external genetalia
- Roughly 3 million per person
- They have two types
- Eccrine Sweat Glands
- Apocrine Sweat Glands
- Contain myoepithelial cells
- Contract upon nervous system stimulation to force sweat into ducts
Eccrine Sweat glands
- Most numerous sweat glands
- Abundant on palms, soles and forehead
- Ducts connect to pores
- They function in thermoregulation
- Which is regulated by sympathetic nervous system
- Their secretion is sweat
Apocrine Sweat Glands
- Confined to axillary and anogenital areas (armpit and genital areas)
- Secrete sweat, fatty substances, proteins
- can be viscous
- odorless until bacterial interaction which leads to body odor
- Larger than eccrine sweat glands
- Ducts empty into hair follicles
- Begin functioning at puberty
- Function is unknown but may act sexual scent gland
- Modified apocrine gland
- Ceruminous gland - in lining of external ear canal, secrete cerumen
- Mammary glands - secrete milk
101
Describe oil glands
- Widely distributed
- Not in thick skin such as palms
- Most develop from hair follicles and secrete into hair follicles
- Relatively inactive until puberty
- Secret sebum
- Oily holocrine secretion
- Softens hair and skin
102
What are the types of barriers the skin provides?
- Chemical
- Secretions from skin act as chemical protection
- Low pH secretion retards/delays bacterial multiplication
- Sebum and definsins kill bacteria
- Melanin
- Defense against UV radiation damage
- Physical
- Flat dead cells of stratum corneum are surrounded by lipids
- Kertain and glycolipids block form a water tight barrier
- Skin cannot be penetrated that easily
- Lipid soluble stuff can get through
- Organic solvents can
- Lots more
- Biological
- Dendritic cells of epidermis presents antigens (bad stuff) to white blood cells
- Macrophage of dermis presents foreign antigens to white blood cells
- DNA electrons absorb UV radiation, converting it to heat
103
What are the functions of the integumentary system? (A Pale Skin Turns Crimson Very Easily)
- Absorption
- Protection
- Sense organ
- Temperature
- Communication
- Vitamin Production
- Excretion
104
What are two bones held together by?
Ligaments
105
What joins a muscle and a bone?
Tendons
106
When looking at the ventral or anterior thoracic region of the body, what are the important bones?
- Clavicles
- Ribs
- Sternum
- Cervical vertebrate (superior)
- Lumbar vertebrate (below)
107
When looking at the dorsal or posterior thoracic region of the body, what are the important bones?
- L/R scapula
- Ribs
- Thoracic Vertebrae
108
When look at the hip bone, what are the important bones?
- Lumbar vertebrae
- ilium (sides)
- sacrum (in the middle)
- ischium (below sacrum posterior side)
- pubis (very bottom)
- coccyx (middle, below sacrum)
109
What are the bones in the arms?
- Humerus (upper arm)
- Radius (outer part of lower arm)
- Ulna (inner part of lower arm)
110
What are all the bones in the hands (no need to list all carpal bones)?
- Distal phalanx (tips of phalanx)
- Intermediate phalanx
- Proximal phalanx
- Metacarpals
- Carpals
Note: Carpals are closer to forearm than metacarpal
111
List all the carpal bones (P ->D) (Sally Left The Party To Take Cathy Home)
Note: This goes from proximal to distal and proximal is closest to forearm
Proximal
- Scaphoid
- Lunate
- Triquetrum
- Pisiform
Distal
- Trapezium
- Trapezoid
- Capitate
- Hammate
112
What are the important bones in the leg or lower limbs (don't include foot)?
- Femur (upper leg)
- Patella (around knee)
- Fibula (outer side of lower leg)
- Tibia (inner side of lower leg)
113
What are all the bones in the foot? (Some + Tall Camels Never Consume Cubes) [camel toe]
- Distal, intermediate and proximal phalanx
- Metatarsals
- Talus
- Navicular
- Cuboid
- Calcaneus
- Medial (close to midline), intermediate and lateral cuneiform
114
Describe the glenohumeral joint
- Articulation (movement) between glenoid cavity of the scapula and head of humerus
- Low stability for maximal movement
- Multiaxial diarthrotic joint
115
Describe the elbow joint
- Articulation between humerus, ulna, radius
- High stability, low movement
- Uniaxial, diarthrotic joint
116
Describe the sacroiliac joint
- Articulation between sacrum and illium
- Maximal stability for minimal movement
- Amphiarthrotic joint (doesn't move too much)
117
Describe the hip joint
- Articulation between acetabulum (socket of ball and socket joint) of the coxal bone and the head of the femur
- Low stability for maximal movement
- Multiaxial diarthrotic joint
118
Describe the knee joint
- Articulation between the tibia, femur and patella
- Low stability for maximal movement
- Multiaxial diarthrotic joint
119
Describe the talocrual joint
- Articulation between tibia, fibula and talus
- high stability, low movement
- Uniaxial, diarthrotic joint
120
What are spinous processes?
The bony parts extending out of the vertebrae, not all parts of the vertebrate have them: C2 to C6
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What are intervertebral foramina?
Gaps in the vertebrae in the middle which contain spinal nerves, not all vertebrae have them
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What are intervertebral discs and describe their structure?
Discs that exist between vertebral bodies.
- They have an outer margin: Annulus fibrosus
- They have an inner margin: Nucleus pulposus
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What is the typical structure of a vertebrae?
It has a body, vertebral foramen, lamina (bony part between foramen) and spinous process
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What is the functional unit of bones?
Osteons
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What is the general structure of a bone?
- Compact bone outside and spongy bone inside
- Central canal of osteons contains neurovascular bundles
- Within an osteon there's also concentric lamellae which is formed by deposition of bone matrix by osteoblasts
- There are mature cells trapped in the bone matrix called osteocytes
- Osteoclasts breakdown and reabsorb the bone matrix
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What determines how much a joint can move (range of motion) and stability?
Shape of bones/joint and the amount of tendons and ligaments
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What are the contents of the vertebral canal vs intervertebral foramina?
VC: Spinal cord and spinal meninges
IF: Spinal nerve roots, posterior root ganglion
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What is the central nervous system comprised of?
Brain + Spinal Cord
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What protects the brain and the spinal cord?
The skull and vertebrae respectively
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What are the different lobes of the brain?
- Frontal (front obv)
- Temporal (sides)
- Parietal (top of the brain)
- Occipital (back of brain)
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What are the lobes of the brain?
- Names after the bones that they sit under
- Frontal, temporal, parietal and occipital
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What are the brain and spinal cord wrapped in?
Meninges
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What are the layers of the meninges?
Superficial or top layer (dura mater)
Intermediate (arachnoid mater)
Deep (pia mater)
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Describe the make up of dura mater
It's fibrous and has lots of sensory nerves in it
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Where is cereobrospinal fluid found?
Between arachnoid and pia mater
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Where is CSF (cerebrospinal fluid) made?
Made by ependymal (a kind of glial cell) in choroid plexus
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How much CSF do we make a day?
500 mL
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Describe how CSF is circulated around the CNS
A limited amount of CSF circulates around the CNS. CSF is reabsorbed by arachnoid granulations which transport it down a pressure gradient to the superior sagittal sinus
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How does blood and other stuff leave the brain?
Venous blood and CSF from superior sagittal sinus leave from internal jugular vein
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How does blood get into the brain?
Internal carotid arteries (anterior circulation), vertebral arteries (posterior circulation)
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What is an anastomosis?
A connection between blood vessels, we use it to describe the connection between anterior and posterior circulation
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Where does arterial blood first get supplied to in the brain?
Brainstem
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What is the brainstem?
Brainstem=midbrain + pons + medulla oblongata
Brainstem connection between spinal cord, thalamus, cerebral and cerebellar hemispheres
Brainstem houses most of the cranial nerve nuclei (collection of neuronal cell bodies).
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What is the thalamus?
the command centre of the brain. It receives all sensory information (apart from olfactory) and determines which cortex to send it to.
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What is the hypothalamus?
sits anterior and inferior to the thalamus and is the command centre of the autonomic nervous system.
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What stuff is the brain comprised of?
Grey matter = cell bodies
White matter = myelinated axons
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What is the corpus callosum?
- The largest white matter tract connecting both left and right hemispheres
- Corpus callosum carries inhibitory fibres to ensure that hemispheres don’t compete with each other and to ensure cortical output is coordinated.
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What is the corticospinal tract?
Chain of two neurons
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Explain the role of primary motor cortexes
The left primary motor cortex(frontal lobe) coordinates voluntary movement on the right side of the body by projecting upper motor neurons down through the brainstem and spinal cord to synapse on lower motor neurons connected to skeletal muscle. Vice versa true for right primary motor cortex.
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What does the somatosensory coretex do?
Theleftsomatosensory cortex receives touch, pain and vibration information from the right-side of the body (via the thalamus). Vice versa is true for right somatosensory cortex.
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What is the limbic system?
connects our sense of smell, memory, and autonomic nervous with our emotional integration centre = amygdala.
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What is the cerebellum?
is important for integrating information from spinal cord, balance, coordination and movement.
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What is the resting voltage of our cells?
-70mV
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Why is our resting membrane potential negative?
- Ion distribution is uneven
- More positive ions go out of the cell than go in (sodium/potassium pump)
- Membrane is more permeable to potassium than sodium, there’s potassium leak channels
- Gibbs-Donnan Effect
- Macromolecules assembled within the cell ionise to form negatively charged compounds plus H+ ions which tend to leave the cells
- So the negative stuff is trapped in the cytoplasm
- Big contribution to the negative charge of inner cell
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What is an absolute refractory period?
No matter what you do, you cannot get an action potential to fire again because the Na+ channels are closed
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What is a relative refractory period?
Neuron can generate action potential but a greater stimulus is needed to produce one because some of the Na+ channels can be activated
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What happens to action potentials if we give a greater stimulus
More action potentials are produced because relative refractory period is overcome rather than a more intense AP happening
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Where does an action potential start happening and how does it propogate (no sensory transduction here)
It starts at the trigger zone and it moves along an axon as the depolarisation spreads from one membrane area to another
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If an electric field or depolarisation happens in both directions, why does action potential only travel in one direction?
Because in one direction there is a relative/absolute refractory period occuring so Na+ channels cannot open so action potential doesn't propogate
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What is the role of myelin?
Myelin (fatty) insulates nerves which speeds up the action potential
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What is saltatory conduction?
- To speed up action potentials we do a few things
- First Schwann cells (PNS) or oligodendrocytes (CNS) sheath the axon with a myelin sheath
- Between them are gaps called nodes of Ranvier
- Action potentials jump from NoR to NoR because they are not covered in myelin
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What is the space between two nerves called?
Synapse
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What is a post synaptic potential?
- Neurotransmission occurs when a neurotransmitter which is in a vesicle is released from the presynaptic neuron to the postsynaptic neuron
- Note: When neurotransmission occurs, we don’t get an action potential forming it’s a POST SYNAPTIC POTENTIAL or PSP
- Basically it’s change in membrane potential at the dendrites of postsynaptic neuron
- It's not all or nothing, it's graded
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Compare and contrast excitatory vs inhibitory post synaptic potentials
- Excitatory PSPs occur when the cell’s voltage gets closer to 0 (it depolarises)
- Inhibitory PSPs occur when the cell’s voltage gets away from o (it hyper-polarises)
- EPSPs increase the chance that an AP will be fired
- IPSPs decrease the chance that an AP will be fired
- Opening Na+ and Ca2+ channels is excitatory
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What does it mean when a PSP is a graded potential and explain what temporal and spatial summation is
- EPSPs and IPSPs are summed up spatially or temporally
- You add up all the EPSPs and IPSPs to get the total membrane potential because they both work in opposite directions
- Temporal summation is when two PSPs happen very close together (boom, 1 sec, boom) and so they add onto each other
- Spatial summation happens when two PSPs happen at the same time, maybe in two different dendrites that are right next to each other
- So there's different grades of PSPs that can form
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State the two general ways neurotransmission occurs
- Direct electrical transmission
- Rare but occurs in cardiac muscle and some neurons and some smooth muscle
- By use of a chemical
- Way more common
- Happens pre much everywhere we need to send electrical signals
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Describe direct electrical transmission in regards to neurotransmission
- APs in the form of ions travel through gap junctions between the presynaptic and postsynaptic neurons
- These gap junctions are made of proteins called connexons
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Describe chemical transmission in regards to neurotransmission
- Neurotransmitters cross the synapse and signal the postynaptic neuron by binding to the receptors on the postsynapstic cell which causes change
- SO what happens from my understanding, an AP comes to the synapse, where a neurotransmitter is being produced and stored
- WHen the AP reaches the end, it triggers a regulated release of these chemicals
- This chemical diffuses to the postsynaptic neuron which binds to a specific receptor
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State the 4 neurotransmitters we need to know
- Noradrenaline
- Acetylcholine
- Glutamate
- GABA
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Explain how acetylcholine is made (reactants, enzymes etc.)
Acetyl-CoA reacts with Choline to produce acetylcholine. Choline acetyltransferase is used as an enzyme
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Explain how GABA is made
Glutamate in the presence of glutamate decarboxylase forms GABA
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Describe the process of releasing neurotransmitters
- So the neurotransmitters are produced at presynaptic neuron and put into vesicles
- They’re docked at the membrane and ready for ****************************second degree**************************** active transport to take them across
- This exocytosis is trigged by an action potential
- Let’s take a close look at the docking
- Remember on the vesicle there’s a v-Snare and a t-Snare on the target membrane
- However, the v-snare (synaptobrevin) and t-snare (SNAP) can’t fuse because they’re blocked by complexin
- This is to make sure we only release shit when we want to
- TO do remove the complexin, we need synaptotagmin which is activated by Ca2+ binding
- So an AP arrives, depolarising the presynaptic terminal
- This causes N-type (neural) voltage gated Ca2+ channels to open
- The calcium binds to the synaptotagmin which displaces the complexin and allows the vesicle to fully fuse with membrane and allows for exocytosis to happen
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Why is it incorrect to say the 4 neurotransmitters determine whether the PSP is excitatory or inhibitory
What the neurotransmitter does (excite or inhibit) isn’t actually dependent on the NTs but more on the receptors
This means the SAME neurotransmitter can be excitatory or inhibitory based on what receptor it acts through
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Describe the two types of neurotransmission receptors
- Ionotropic receptors
- Open/close ion channels
- They’re ligand gated ion channels
- Metabotropic receptors
- Activate enzymes
- Ligand binding outside cell activates enzyme inside cell
- This means the SAME neurotransmitter can be excitatory or inhibitory based on what receptor it acts through
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How do we stop neurotransmitters from being released all the time?
- We can uptake neurotransmitters
- Uptake by presynaptic neuron or glial cells
- Most neurotransmitters are stopped by this
- Uptake ports take in neurotransmitters as they’re being released and as diffusion gradient decreases, it becomes easier to take these neurotransmitters in
- Neurotransmitter degradation
- Enzymes within the synapse chew up neurotransmitter molecules
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What is the name of the enzyme that breaks down acetylcholine
Acetylcholinesterase breaks it down into Acetyl-CoA + choline
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Name all of the cranial nerves (Oh Oh Oh, to touch and feel very good vests, so handsome)
Olfactory Nerve
Optic Nerve
Oculomotor Nerve
Trochlear Nerve
Trigeminal Nerve
Abducens Nerve
Facial Nerve
Vestibulocochlear Nerve
Glossopharyngeal Nerve
Vagus Nerve
Spinal Accessory Nerve
Hypoglossal Nerve
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List the order of functions of cranial nerves (state the menemonic)
(Some say marry money but my brother says big brains matter more)
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What is the major function of the olfactory nerve?
Sense of smell
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What is the major function of the optic nerve?
Vision
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What is the major function of the occulomotor nerve?
Eye movements (pupillary constriction and muscle of upper eyelid).
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What is the major function of the trochlear nerve?
Eye movements (intorsion and downward gaze). Supplies motor axons to superior oblique
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What is the major function of the trigeminal nerve?
Involved in somatic sensations from face, mouth, cornea and muscles of mastication (chewing)
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What is the function of the abducens nerve?
Eye movements (abduction or lateral movements of the eye)
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What is the function of the facial nerve?
Controls the muscles of facial expressions, taste from anterior tongue and controls lacrimal and salivary glands (submandibular and sublingual)
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What is the function of the vestibulocochlear nerve?
Hearing: Sense of balance
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What is the function of the glossopharyngeal nerve?
Sensation from posterior tongue and pharynx, taste from posterior tongue, carotid baroreceptors and chemoreceptors, salivary glands (parotid salivary glands)
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What is the function of the vagus nerve?
Autonomic functions of the gut, cardiac inhibition, sensation from larynx and pharynx, muscles of vocal cord and swallowing
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Spinal Accessory Nerve function
Shoulders and neck muscles
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What is the function of hypoglossal nerve
Movements of the tongue
