Midterm 2- Animal Physioloigy Flashcards
Four themes of Physiology
1.Physiological processes obey physical and
chemical laws
2. Physiological processes are shaped by
evolution
3. Physiological processes are usually
regulated
4. Physiology is integrative
Traits of animals
- Multicellularity, with cells that Lack cell wall and Have an extensive extracellular matrix
- Heterotrophy-They obtain necessary carbon compounds from other organisms
- Motility- They move under their own power at some point in their life cycle
Anatomy
refers to an organism’s physical structure or form
Physiology
the study of how the physical structures in an organism function
Adaptation
a genetic change in a population in response to
natural selection exerted by the environment
Acclimatization
a phenotypic change that occurs in an individual
in response to environmental fluctuations
Homeostasis
as stability in chemical and physical
conditions within an organism’s cells, tissues, and organs
Two response mechanisms that help to maintain homeostasis
1)Regulate-Control the body to counteract the effect of the environment
2)Conform-Change the conditions of the body to match the environment
Set Point
a normal or target value for that
variable
Three parts of a homeostatic enviroment
- A sensor-structure that senses some aspect of the external or internal environment
- An integrator-evaluates the incoming sensory information by comparing it to the set point and determining whether a response is necessary
- An effector-any structure that helps restore the internal condition being monitored
Negative Feedback
effectors reduce or oppose the direction of change in internal conditions
Three features of a negative feed back loop
- Redundancy-Multiple mechanisms are in place to solve a change in state
- Antagonistic pairs-A set of systems that work to do opposite activities which regulate the same system
- Continuous feedback
Tissue
a group of similar cells that work together as a unit to perform the same function
Four types of tissue
1)Connective
2)Nervous
3)Muscle
4)Epithelial
Connective tissue
Consists of cells loosely arranged in a liquid, jellylike, or solid matrix that holds things together
Four types of connective tissue
1)Loose connective tissue
2)Dense Connective tissue
3)Supporting connective tissue
4)Fluid connective tissue
Loose connective tissue
contains an array of fibrous proteins in a soft
matrix that hold things together loosely such as fat
Dense connective tissue
contains a matrix dominated by tough collagen
fibers that are secreted by fibroblasts and holds the body together tightly including ligaments and tendons
Supporting connective tissue
has a firm extracellular matrix that functions and support and protection includes bones and cartilage
Fluid connective tissue
cells surrounded by a liquid extracellular matrix functions as transport and and includes things like blood
Nervous tissue
Transmit electrical signals by changes in permeability of the cell’s plasma membrane to ions (action potentials)
Components of Neurons
1)dendrites, which transmit electrical signals
from adjacent cells to the neuronal cell body
2)axons, which carry electrical signals from the cell body to other cells
Muscle tissue
functions in movement-related physiological activities
Skeletal muscles
attaches to bones and exerts force on them when it contracts
Cardiac muscles
makes up the walls of the heart and is responsible for pumping blood throughout the body,under involuntary control
Smooth muscle
lines the walls of the digestive tract and blood vessels controlling movement through those systems
Three types of Muscle tissue
1)Cardiac
2)Skeletal
3)Smooth
What muscle type is this
Smooth
What muscle type is this
Skeletal
What muscle type is this
cardiac
Epithelial tissue
tissues that cover the outside of the body, line the surfaces of organs, and form glands
Gland
a group of cells that secrete specific molecules or solutions
Epithelia
provide protection and act as “gatekeepers” for the selective movement of water and nutrients across their inner and outer surface
Organ
a structure that serves a specialized function and consists of several tissues
Layers of Epithelial
Apical-faces away from other tissue
Basal-faces the interior of the animal
Basal lamina-Connects epithelial to other tissues
Organ system
consist of groups of tissues and organs that work together to perform one or more functions
Metabolic rate
overall rate of energy consumption
basal metabolic rate
the rate at which an animal consumes
oxygen while at rest with an empty stomach, under normal temperature and
moisture conditions
Methods to increase the surface area to metabolic ratio
1)Flattening-use of sheet like structure ex.gills
2)Folding-Surface is folded many times to increase surface area ex.villi
3)Branching-structure is broken into many smaller structures ex. capillaries
endotherm
produces adequate heat to warm its own tissue
Ectotherm
relies on heat gained from the environment
Homeotherms
keep their body temperature constant
Poikilotherms
allow their body temperature to change depending on environmental conditions
Torpor
a temporary drop in body temperature
Conduction
the direct transfer of heat between two physical bodies that are in contact with each other
Radiation
the transfer of heat between two bodies that are not in direct physical contact
Evaporation
the phase exchange that occurs when liquid water becomes a gas
Thermal conductivity
Conduction is the direct transfer of
heat between two physical bodies
that are in contact with each other
Convection
Transfer of thermal energy between an object and an external medium that is moving
Insulation
Layer of air/water/tissue which decreases heat loss Ex.Blubber,Hair,Feathers,Air, Water
Allen’s rule
Species found in
cold climates display shorter limbs
and appendages than species
located in warm environment
Bermans rule
Species with larger body sizes are found in
colder climates, whereas smaller
body-sized species are located in
warm areas
What does this depict, describe an example
Counter current flow, the tongue of a blue whale has this method to help conserve heat
What does this depict
Concurrent flow
Traits of animals
-Lack cell walls
-Have an extensive extracellular matrix
-They obtain necessary carbon compounds from other organisms
-Most ingest their food rather than absorbing it
-They move under their own power at some point in their life cycle
4 requirements for all cells
1.Proteins—perform most of the cell’s functions
2. Nucleic acids—store, transmit, and process information
3. Carbohydrates—provide chemical energy, carbon, support, and identity
4. Plasma membrane—serves as a selectively permeable membrane barrier
Why is it beneficial to compartmentalize the cell?
- Separation of incompatible chemical reactions
- Increasing the efficiency of chemical reactions
Nucleous
Region of the nucleus that is responsible for synthesizing ribosomal RNA and assembling ribosomal sub units
Functions of the nucleus
-Contains the cell’s chromosomes
– Each chromosome occupies a distinct area
– Densely packed sections of DNA at the periphery
– Loosely packed sections of DNA toward the interior
Rough endoplasmic reticulum
Synthesizes proteins that will be Shipped to another organelle, Inserted into the plasma
membrane and Secreted to the cell exterior such as messenger proteins,transports/pumps, or catalyzing reactions
Smooth endoplasmic reticulum
Contains enzymes that catalyze
reactions involving lipids, Synthesize lipids needed by the organism, Break down lipids and other molecules that are poisonous
and act as a reservoir for Ca2+ ions
Golgi apparatus
Is formed by a series of stacked,
flat, membranous sacs called
cisternae with a cis side facing the nucleas and a trans side facing the cytoplasm whos main function is to Processes, sorts, and ships
proteins synthesized in the rough
ER
Cis side of golgi
surface closest to the nucleus that receives products from the rough ER
Trans side of the golgi
Surfaceoriented to plasma membrane, main job is to ship products of the rough ER out to other
organelles or the cell surface
Lysosomes
are recycling centres found only in animal
cells that Digest macromolecules and
export monomers to the cytosol
three lysosomes recycling pathways
1)Receptor mediated endocytosis-a process by which cells absorb metabolites, hormones, proteins – and in some cases viruses – by the inward budding of the plasma membrane
2)Phagocytosis-process by which certain living cells called phagocytes ingest or engulf other cells or particles
3)Autophagy damaged organelle is engulfed by lysosome and digested releasing monomers into cytoplasm
Peroxisome
– Centre of redox reactions
– Liver cell peroxisomes contain enzymes
that oxidize the ethanol in alcoholic
beverages
– Involved in detoxifying reactive
molecules
Mitochondria
Supply the cell with ATP and are composed of The inner one is folded into a
series of sac-like cristae and The solution inside the inner membrane mitochondrial matrix
Functions of cytoskeleton
– Structural stability
– Cell division
– Cell motility
– Maintaining/changing cell shape
– Transports materials within the cell
– Organizes the organelles and other cellular structures into a cohesive
whole
Three types of cytoskeletal elements
1.Actin filaments (microfilaments)
2.Intermediate filaments
3.Microtubules
Actin Filaments
The smallest cytoskeleton component formed by two strands of actin twisted around one another with a fast growing plus end and slow growing minus end these filaments help define the shape of the cell as well as mediate movement
Cell crawling
occurs via actin filaments growing in one direction, which causes the cell to move
Intermediate Filaments
Are defined by size rather
than composition as Many types exist, each
consisting of a different
protein, their main function is to provide structural support to the cell
Microtubules
the largest cytoskeletal elements that are composed of hallow tubes of tubulin which grow along they plus end. They provide the tracks along which vesicles move and separate chromosomes as well as provide cell stability
kinesin
Uses ATP to do mechanical
work allowing it to “walk” along a microtubules through a series of conformational changes
Where is this? How can you tell?
Testis, it generates a lot of lipids which you can tell from the over abundance of smooth er
Where is this? How can you tell?
Animal pancreas,responsible for digesting so lots of lysosomes
Where is this? How can you tell?
Cardiac muscles, uses a lot of atp so lots of mitochondria
plasma membrane
It’s function is to create an environment inside the cell which is different from conditions outside
Extra cellular matrix
Composed of a fibrous component(mostly collagen) which forms a flexible extracellular layer and a ground substance is made of proteoglycans that attracts water and forms a gel
Three types of structures involved in holding animal cells together
-Tight junctions
– Desmosomes
-Gap junctions
What is this, what is its function
Tight junction, seals the cell together with stitches that provide a watertight seal found primary in epithelial cells
What is this, what is its function
Desmosomes, connects the cytoskeleton of cells, Resist pulling and shearing forces and are found in epithelial and muscle tissue
What is this, what is its function
Gap junction, act as a channel between cells allow the flow of small molecules between cells
Importance of direct connection between cells
-Ions and small molecules can pass between cells
– May regulate gene expression
– May activate on inactivate proteins
5 categories of chemical signals
- Autocrine signals
- Paracrine signals
- Endocrine signals
- Neural signals
- Neuroendocrine signals
Autocrine signals
affect the same cell that releases them such as cytokins which amplify the response of a cell to a stimulus
Paracrine signals
diffuse locally and act on target cells near the source cell such as insulin and glucagon inside of the liver
Endocrine
signals are carried to distant cells by blood or other body fluids produced by a gland
Neural signals
diffuse a short distance from a presynaptic cell to a postsynaptic cell, where they bind to a membrane receptor and result in
a change in the membrane potential, very fast because action potentials propagate
rapidly and have only a short distance to diffuse across the synaptic cleft
Neuroendocrine
signals are released from neurons but are
considered hormones because they are carried by blood or other body fluids and act on distant cells an example being anitdeuretic hormone which is produced in the hypothamus but must travel to the kidneys
two methods for a cell to respond to an incoming chemical signal
1)A change in which genes are being expressed in the target cell
2)A change in the activation or deactivation of a particular target protein that
already exists in the cell
Hormones
information-carrying molecules that are secreted from a cell which circulates in the body
acting on target cells far from the signalling cell, these molecules act as integrators in maintaing homeostasis
Animal hormone types
1)Peptides and polypeptides, chains of amino acids linked by peptide bonds
2) Amino acid derivatives
3) Steroids, which are a family of lipids distinguished by a four-ring structure
signal receptor molecules in response to hormone signals
Change shape and activity after binding to a hormone but only cells with appropriate signal receptors will respond to a particular
signalling molecule
Lipid-soluble hormones
Hormones capable of diffusing across the plasma membrane, they bind to receptors are in the target cells’ cytoplasm where they trigger change in the cell’s activity directly
Lipid insoluble hormones
Large hormones which cannot cross the plasma
membrane, they bind to receptors on the cell’s plasma membrane
The hormone–receptor complex
Proteins that hormones. Once bound, the hormone/receptor complex initiates a cascade of cellular effects resulting in some modification of physiology and/or behaviour via alteration of gene expression
Membrane receptors
Bind to lipid insoluble hormones and converts the extracellular signal into a intracellular signal via signal transduction
Two methods for signal transduction
1)The signal may be amplified ,signalling molecule activate several downstream molecules increasing the signal strength
2)Signal is diversified, the single signal can lead to several changes in the cell
G proteins
trigger production of a second messenger after being activated by a signal receptor
G-Protien coupled signalling
- A signalling molecule binds to its membrane receptor
- The associated G protein exchanges GDP for GTP Spliting the signal into two parts
- The active G protein subunit activates a nearby membrane enzyme that catalyzes the production of a second messenger
Secondary messengers
Small molecules that can be produced rapidly and diffuse quickly throughout the cell which help to amplify a signal
protein kinases
add a phosphate group to other proteins which can activate or deactivate them
Enzyme-linked receptors
Embedded in the membrane and bind directly to a hormone and lead to the catalyzing of a reaction inside of the cell
Ion channel receptors
Proteins that when activated allow ions to leave or enter a cell
Insulin
a small protein hormone produced by the pancreas when blood glucose level is high
Insulin signalling in the body
When fat or muscle cells are bound with insulin glucose transporters are added to the cells membrane allowing the cell in import the extra glucose
Glucagon
causes glucose-storing cells in the liver to export
glucose to the blood, increasing blood glucose levels
Effect of glucose content on the body
Low: Not enough fuel for the brain and body to function
High:Toxic to neurons and organ systems by decreasing the PH of the blood
Draw a diagram for Lipid insoluble signal transduction
Draw a diagram for steroid hormone action
Main Functions of the plasma membrane
– Keep damaging materials out of the cell
– Allow entry of materials needed by the cell
– Facilitate the chemical reactions necessary for life
Lipids
Carbon-containing compounds that are
Largely nonpolar and hydrophobic
Hydrocarbons
Hydrophobic molecules containing only carbon and hydrogen in equal shared bonds
fatty acid
a hydrocarbon chain bonded to a carboxyl (–COOH)functional group that can be saturated or unsaturated
Three lipid types found inside cells
1)Fats composed of three fatty acids linked to glycerol
2)Steroids family of lipids with a distinctive four-ring structure
3)Phospholipids consist of a glycerol linked to a phosphate group and to either two chains of (isoprene or) two fatty acids
Phospholipids
Glycerol linked to a polar group and two fatty acid tails, its main function is to form the bilayer of cells and is an ampiphatic molecule
Saturated fatty acid
hydrocarbon chains consist
of only single bonds between the
carbons
Unsaturated fatty acid
hydrocarbon chains have
one or more double bonds in the
hydrocarbon chains
Beneficial properties of having membranes made of lipids
1)Flexible allowing the cell to change shape
2)Repairable, lipids always reform to create a continuous surface when damaged
3)Expandable- You can continue to add lipids to increase the cell size
Rank the permeability of different molecules trying to pass the lipid bilayer
Small non polar molecules>Small uncharged polar molecules>Large uncharged polar molecules>Small ions
Factors that influence the permeability of the phospholipid bilayer
–Number of double bonds between the carbons in the phospholipid’s fatty acid tail
– Length of the tail
–Number of cholesterol molecules in the membrane
–Temperature
How does tail length influence membrane permeability
Hydrophobic interactions become stronger as saturated hydrocarbon tails increase in
length
How does number of double bonds affect membrane permeability?
Double bonds decrease van der whals forces meaning lipids pack together less tightly increasing the permeability
How does adding cholesterol affect membrane permeability?
Adding cholesterol to membranes increases the density of the hydrophobic section decreasing permeability but increasing fluidity
How does temperature affect membrane fluidity?
Membrane fluidity decreases as temperature drops because molecules in the membrane move slower,tails pack closer,and the decrease in fluidity decrease permeability
homeoviscous adaptation
Ability to maintain membrane fluidity in low temperatures via the following mechanisms
1)Decrease fatty acid chain length
2)Decreassed sautration of tails
3)Increase cholesterol
4)phosphatidylethanolamine instead of phosphatidylcholine
Passive transport
substances diffuse across a
membrane in the absence of an outside energy source consisting of diffusion and facilitated diffusion
integral membrane proteins
Protiens which embed through the membrane, they have a hydrophobic exterior to slot into the membrane
Peripheral membrane proteins
Found on either the interior or exterior surface of the membrane they sit in the bilayer but do not pass it
fluid-mosaic model
The membrane is a fluid, dynamic mosaic of
phospholipids and proteins
Facilitated diffusion
The selective process of passive movement of molecules along the concentration gradient
Channel protein
form pores that selectively admit certain ions like aquaporins
Carrier Protein
undergo a conformational change to transport
specific molecules across the
membrane like GLUT-1 for glucose transport
Gated channels
Channels that open or close in response to a signal either in the form of a bonded protein or an electric signal
Active transport
Moves substances against their gradient and requires an input of energy like ATP
Pumps
membrane proteins
that provide active transport of
molecules across the membrane
Sodium potassium pump mechanism
1)3 Sodium binds to the active site
2)ATP is consumed, the phosphate group cause a conformational change in the pump which releases the sodium across the membrane
3)2 Potassium binds to the changed active site
4)Phosphate is cleaved and the pump returns to it’s native state bringing the potassium across the membrane
Secondary active transport
utilises an existing gradient of one
molecule to power the transport of another
Symporters
transport solutes against a
concentration gradient, using the energy
released when another solute moves in
the same direction along its
electrochemical gradient
Antiporters
actively transported solute moves in the
opposite direction
coupled transporter
membrane proteins use the gradient of ions to power the movement of glucose, atp is consumed in creating the gradient but not in transporting the molecules through the membrane
Ion channels
specialized membrane proteins that form pores, or openings, in a membrane which facilitate the diffusion of ions
Electrochemical gradients
occur when ions build up on one side of a
plasma membrane establishing an electro chemical gradient onto which ions can diffuse down
Two types of nervous system
1)Nerve nets where nerve cells are diffused around the organism
2) Central nervous system which includes large numbers of neurons aggregated into
clusters called ganglia
Interneurons
enabling communication between sensory or motor neurons and the central nervous system
Motor neurons
send signals to effector cells in glands or muscles
Three components of the nerve cell
- Cell body, or soma.
- Dendrites
- Axons
membrane potential
a separation of charge immediately adjacent to the plasma membrane
resting potential
The negatively charged baseline for the neuron when not sending/ receiving signals
electrochemical gradient
combination of an electric gradient and a concentration gradient
Ion gradient of neurons
Inside cell: Low Na+ and Cl− , High K+ and some organic
anions
Outside: High Na+ and Cl− predominate
Roll of potassium channels in maintaining the resting potential
K+ wants to diffuse outside of the cell through its channels, at equillibrium this cuases the inside of the cell to have a net negative charge
Nernst equation
Equation which helps to calculate the membrane potential at equillbrium it is calculated via the following formula
The Goldman equation
Equation which calculates membrane potential accounting for multiple ions and their permeabilities
Resting membrane potential
-65 mV
Equilibrium potential for Na+
+60 mV
Equilibrium potential for K+
-90 mV
What happens to membrane potential as permeability for that ion increases?
Membrane potential moves towards the equilibrium value of the ion whose permeability has been increase
action potential
a rapid, temporary change in a membrane
potential. Occurring in three phases 1)Depolarization 2)Re polarization 3)Hyperpolarization
Depolarization
the phase in
which the membrane becomes less
negative and moves toward a
positive charge triggered by movement of Na+ ions
repolarization
changes the membrane back to a negative
charge, it is triggered by the closing of certain ion channels and the opening of other ion
channels in the membrane
Hyperpolarization
when the membrane becomes more negative
than it was during the resting
potential
threshold potential
the change in potential from -65 to -55 which is what cause a signal to be sent. Any lower than -55 and the signal will not be sent and depolarization will not continue
relative refractory period
After a signal has been sent the neuron becomes hyperpolarized or below the regular threshold meaning more stimuli is needed to re excite the neuron to fire again
Voltage clamping
technique which allows researchers to hold an axon at any voltage and record the electrical currents that occur
Patch clamping
a form of voltage clamp that allows the isolation and measurement of electric activity of of a single ion channel
Describe the conditions of this phase
Na and K channels are closed
K+ permeability dominates
Describe the conditions of this phase
Depolarization begins at -55
Voltage gated Na+ channels open and flood the cell
Describe the conditions of this phase
Repolarization
Na+ channels inactivating and the K+ channels open allowing ions to move out of the cell
Describe the conditions of this phase
Hyper polarization
Na+ channels completly closed off and K+ let excess K+ flow out causing a negative charge in the cell
Steps in propagating action potential down an axon
1)The influx of Na+ at the start of an action potential repels intracellular
cations
2)As positive charges are pushed farther from the initial sodium channels,
they depolarize adjacent portions of the membrane
3)Nearby voltage-gated Na+ channels open when the adjacent membrane
reaches threshold due to displaced Na+
Why can action potentials only propagate in one direction?
- Na+ channels inactivate after opening upstream - absolute refractory period
2.The after-hyperpolarization phase – relative refractory period,The membrane is more negative than the resting potential - keeps the positive charges that spread upstream from triggering an action potential
Axon diameter and speed
Cations meet less resistance in axons with large diameters than those in narrow axons as a result, the charge spreads along the membrane more quickly
myelin sheath
acts as electrical insulation, preventing ions from leaking out across the plasma
membrane during the propagation of an action potential
Nodes of Ranvier
breaks in the myelination where voltage-gated Na+ and K+ channels are clustered at these nodes
saltatory action potential conduction
Action potentials “jump” from node to node down a myelinated axon by sending enough potential down the short distance to regenerate the next action potential at the nodes.
neurotransmitters
Chemical messengers that
transmit information from one
neuron to another neuron,
muscle, or gland
synaptic cleft
Separation between the presynaptic and post synaptic neuron which neurotransmitters travel through
Transfer of information from pre synaptic to post synaptic neuron
1) Action potential arrives at the end of the axon
2)Depolarization opens voltage-gated calcium
channels located near the synapse in the plasma membrane of the presynaptic neuron, and calcium flows in down its electrochemical gradient
3)In response to the influx of calcium, synaptic vesicles fuse with the presynaptic membrane, then release the neurotransmitter into the
synaptic cleft by exocytosis
4)Neurotransmitters bind to
receptors on the postsynaptic
membrane, acting as a ligand—
a molecule that binds to a
specific site on a receptor protein
5)The response ends as
neurotransmitters are
removed from the synaptic
cleft.
Fate of neurotransmitters after the signal has been sent
1)Diffuse away
2)Digested by enzymes
3)Taken up by the glia
ligand-gated ion
channels
The ligand-gated ion channel
opens in response to the binding
of the neurotransmitter and allows
flux of ions down an
electrochemical gradient
metabotropic receptors
G-protein coupled receptors that activate enzymes or ion channels that can lead to a secondary messenger capable of causing changes in genomics expression
Excitatory postsynaptic
potential
Neurotransmitter action on the postsynaptic cell that causes depolarization
Inhibitory postsynaptic potential
neurotransmitter action leads to postsynaptic membrane hyperpolarization
Factors that affect EPSP/IPSP magnitude
– The type of NT receptor
– Amount of NT released
– How long the NT remains in the
synapse
– Density of NT receptors on the
postsynaptic neuron
axon hillock
Part of the neuron which sums the EPSP and IPSP potentials and integrates them to send or not send a signal down the axon, if the depolarization is great enough a signal is fired
Central Nervous System
Composed of the brain and spinal cord
Peripheral Nervous system
Afferent division and Efferent division(Somatic and Autonomic(Parasympathetic and sympathetic nervous systems))
Labels and Functions
A) Cerebrum, conscious thought and memory
B)Cerebellum, complex motor patterns
C)Brain Stem:Connects brain to spinal cord and regulates the heart,lung, digestion
D)Diencephalon:Relays sensory information to the cerebellum and controls homeostasis
Labels and Functions
a)frontal lobe:important for voluntary movement, expressive language and for managing higher level executive functions
b)parietal lobe:responsible for receiving and processing sensory input
c)Temporal Lobe:helps you use your senses to understand and respond to the world around you
d) Occipital Lobe:visual processing area of the brain
Corpus callosum
Region of the brain consisting that connect the left and right cerebral hemispheres allowing communication from both sides of the brain
Broca area
Associated with speech production and articulation, they can form the thought but are unable to say it
Wernicke area
the speaker must momentarily activate knowledge about the sequence of consonant and vowel speech sounds (phonemes) that form the word to be spoken. This mental stage prior to articulation is known as phonologic retrieval.
Learning
A change in behaviour that results from a specific experience in an individuals life via changes in biochemical signalling or structural changes like synapse density
Aplysia Siphon experiment
When you shock the tail and touch the siphon of a sea slug the shock causes K+ gates in the neurons to get phosphorylated and prolonging depolarization increasing the sensitivity to the stimulus
Voluntary muscles
Contract in response to counscious thoughts and are stimulated by neurons in the somatic division
Involuntary muscles
Contract only ins response to unconscious electrical activity and are controlled by neurons in the autonomic division
Smooth muscle cells
Unbranched, lack sacromeres, unstriated, singularly nucleated, they are essential in controlling lungs,blood vessels,digestion,bladder,reproduction
Cardiac Muscle Cells
Branched, Contain Sarcomeres, straited, multi nucleated, moves involuntary following spontaneous depolarization,makes up the walls of the heart and is responsible for pumping blood throughout the body as part of the
circulatory system
Skeletal Muscle Cells
Unbranched, Sacromeres, Multinulceated, Striated, Exert a pulling force on the bones when contracted and are controlled only through somatic motor neurons
3 types of muscle fiber
1)Slow- Slow oxidative
2)Fast- Glycolosis
3)Intermediate- Glycolosis and oxidative
Slow Muscle Fiber
High myoglobin content, contracts slwoly because myosin hydrolizes ATP slowly. Uses slow oxidative process with many mitochondria in the tissue allowing for it to fatigue slowly
Fast Muscle Fiber
Low myoglobin, hydrolozises atp quickly but tires quickly due to using glycolsis to power it
Intermediate Muscle Fiber
High myoglobin, able to perform both glycolisis and anerobic respiration
Parallel arrangement of muscle fibre
Maximizes length changes, produces a small force and pulls width wise on the muscle, found in areas like thigh and help create fast movement
Pennate arrangement of muscle fibre
Fibres are organized into two flexed sheets that maximize force and pull a short length, found in muscles like the calf that are necessary for load bearing
Skeletal Systems Functions
1)Protection from biological intrusions
2)Maintain posture
3)Re-extension of shortened muscles
4)Transfer of muscle forces to other parts of the body and environment
Three types of skeletal systems
1)Hydrostatic skeleton; uses pressure of enclosed body fluids and soft tissue for support
2)Exoskeleton; Rigid structure outside the body attached to muscles via apodemes
3)Endoskeleton; rigid structure inside the body
Vertebrae skeleton types
1)Bones:cells in a hard matrix
2)Cartilage: Cells scattered in a gelatinous matrix of polysaccharides
3)Ligaments: Bands of fibrous connective tissue that binds bones to other bones
Tendon
Attach the bones to the skeletal muscles
Types of Bone Tissue
1)Osteoblasts
2)Osteoclasts
3)Osteogenic cells
4)Osteocytes
Osteoblasts
Bone building cells that generate protein and calcium rich extracellular matrix
Osteoclasts
Bone reabsorbing cells that secrete acid onto bone tissue when calcium levels are low leaking them into blood
Osteogenic cells
Undifferentiated stem cells with high mitotic activity which develop into osteoblasts
Osteocytes
Calcified osteoblast, the primary cell of mature bone
Vitamin D and its function
Helps us reabsorb calcium in our small intestine, can be created in our body when we are struck with enough UV light, without it causes osteoporosis and rickets
Components of Sacromeres
1)Actin thin filaments
2)Myosin thick filaments
Myosin head is bound to the actin filament which catalyze the hydrolysis of ATP, the sliding of the filaments is what causes muscle contractions
Interaction of Actin and Myosin
1)ATP binds to myosin head, causing a conformation change that releases the head off of the actin
2)ATP turn into ADP, myosin head neck straightens and head pivots into the cocked position
3)Phosphate is relased and head returns to original position
4) ADP is released and myosin filaments is ready for binding to another ATP molecule
3D structure of sacromere
Thick filaments surrounded by 6 thin filaments
Role of calcium in muscle contraction
Calcium ions initiate muscle contraction by binding to troponin helps move the tropomyosin out of the way exposing the myosin binding site on actin
Steps in the initiation of contraction
1)Action potential triggers the release of acetocholine form neuron into synaptic cleft
2)ACH diffuses accross syanmtpic cleft triggering Na+ channels to open triggering depolarization
3)Action potential moves across the plasma membrane into T-Tubule
4)Sarcoplasmic reticulum interacts with action potential in T-Tubules releasing Ca2+
5)Myosin binding sites in actin are exposed allowing contraction
