Midterm 1 Flashcards
Physiology
- The Study of body functions
What are the two processes that explain body functions?
1) Teleological –> Why?
2) Mechanistic –> How?
Anatomy
-The study of the structure of the body
Structure-Function relationship
Inseparable
Levels of the body
1) Chemical level
2) Cellular level
3) Tissue level
4) Organ level
5) Body system level
6) The organism level
Chemical Level
Atoms
Cellular Level
The basic unit of life
Tissue Level
a specialized group of cells
Organ Level
several tissue types
Body system Level
related organs
Organism Level
functional whole body
Homeostasis
maintenance of a relatively stable environment by…
1) minimizing change
2) responding to change
ECF
Extracellular fluid
- Fluid environment in which the cells live (fluid outside the cell)
- 2 components –> plasma and interstitial fluid
ICF
Intracellular fluid
-fluid contained within all body cells
Homeostasis in Action: Circulatory System
- carries materials from one part of the body to another
Homeostasis in Action: Digestive System
- breaks down dietary food
- transfers water and electrolytes
- eliminates undigested food residues
Homeostasis in Action: Respiratory System
- receives and eliminates O2 to and from the external environment
- maintenance of proper pH of internal environment
Homeostasis in Action: Urinary System
- removes excess water, salt, acid, and other electrolytes from plasma and eliminates them in urine
Homeostasis in Action: Skeletal System
- provides support
- storage reservoir for calcium
- enables body movement
- bone marrow is the ultimate source of all blood cells
Homeostasis in Action: Muscular System
-moves the bones
Homeostasis in Action: Integumentary System
- outer protective barrier
- important in regulating body temperature
Homeostasis in Action: Immune System
- provides protection
- repairs and replaces injured or worn-out cells
Homeostasis in Action: Nervous System
- controls and coordinates bodily activities that require rapid responses
- detects and initiates reactions to change in the external environment
Homeostasis in Action: Endocrine System
-regulate activities that require duration rather than speed
Homeostasis in Action: Reproductive System
- not essential for homeostasis
- essential for perpetuating species
Feedforward
responses made in anticipation of a change
feedback
responses made after a change has been directed
types of feedback
Negative and Positive
Negative feedback
- Primary type of homeostatic control
- opposes an initial change
Positive feedback
-amplifies an initial change
T/F: Disruptions in homeostasis can lead to illness and/or death
True
Plasma Membrane
- A.K.A cell membrane
-Separates the cell contents from its surroundings (forms a barrier (ICF from ECF))
-Controls movement of molecules into and out of the cell
(transport and communication with the external environment)
Nucleus
- enclosed in a double-layered nuclear envelope (separates the nucleus from the cytoplasm and has nuclear powers)
- Contains genetic material (DNA)
- Houses nucleolus
Nuclear Pores
regulate the movement of material into and out of the cell (cellular transport)
Nucleolus
- “little nucleus”
- involved in the synthesis of ribosomal RNA
Functions of DNA
1) directs protein synthesis
2) serves as a genetic blueprint during cell replication
Cytoplasm
- Everything but the nucleus
- Consists of: Organelles, Inclusions (NOT membrane-bound), cytosol (gell like mass that holds the cytoskeleton)
Organelles
- Membrane-bound components of cells
- “little organs”
- distinct, highly organized structures
Examples of Organelles
- Endoplasmic reticulum
- Golgi complex
- lysosome
- peroxisome
- mitochondrion
Endoplasmic Reticulum (ER)
- interconnected membrane tubes
- function: protein and lipid manufacturing
- Two types: Smooth and Rough
Smooth ER
- lipid synthesis
- hormone synthesis
- No Ribosomes
- package proteins from RER
Rough ER
- Protein synthesis
- Ribosomes present
Golgi complex
- exocytosis
- closely associated with ER
- flattened slightly curved sacs called cisternae
- functions: 1) process raw materials into finished products 2) sorts and directs finished products to their final destination
- receives packaged proteins from SER
Lysosomes
- membranous sacs containing hydrolytic enzymes
- extracellular material enters the cell by endocytosis
- uses: Phagocytosis, autophagy
Peroxisomes
- sacs that house oxidative enzymes
- neutralize H2O2 by using enzymes into H2O and O2
Mitochondria
a) energy organelle
- ATP production
- contains enzymes for citric acid cycle and ETC
b) enclosed by a double membrane
- inner and outer
- inter-membrane space
- matrix
Non-membranous organelles
- Ribosomes
- Vaults
- Centrioles
Ribosomes
- Synthesized in nucleolus
- Present in RER
Vaults
- octagonal shape
- function unknown: maybe TRANSPORT organelles OR STORE DRUGS (drug resilience)
Centrioles
-Direct DNA movement during cell division
Mitosis
- 2 identical cells
- Somatic cells
- diploid
Meiosis
- Haploid cell
- Crossing over
- Sex cells
Stages of Mitosis
1) Prophase
2) Metaphase
3) Anaphase
4) Telophase
Stages of Meiosis
1) Meiosis 1
2) Meiosis 2
T/F: Cells can die
True
Messy cell death
AKA Necrosis
-Cells die from physical trauma, toxins, lack of O2
(swell, organelles die, rupture)
Tidy cell death
AKA programmed, Apoptosis
-Shrink, organelles fall apart, self-destruction
Tay-Sachs Disease
LYSOSOMES
- storage disorder
- missing enzyme hexosaminidase
- leads to loss of muscle coordination, vision, hearing loss, paralysis
- death
- common is Jewish boys
McArdle disease
MITOCHONDRIA
- metabolic disorder
- unable to break down glycogen into glucose
- Cramps, pain, extreme fatigue
Kearns-Sayre Disease
MITOCHONDRIA
- effects the eyes (retina becomes pigmented)
- heart block, weakness of limbs, deafness
Amyotrophic Lateral Sclerosis
INTERMEDIATE FILAMENTS (CYTOSKELETON)
- motor neuron disease (muscle)
- extreme levels of glutamate (toxic levels)
- mitochondrial dysfunction (energy dysfunction –> extreme fatigue)
- misfolded intracellular proteins
- death
Mitochondria
- Energy organelle
- -> ATP production
- -> Contains enzymes for ETC and Citric Acid Cycle
- Enclosed by a double membrane
- -> inner and outer
- -> intermembrane space
- -> Matrix
ATP Production
-Glycolysis (cytoplasm)
-Citric Acid Cycle (mitochondria)
-Electron transport chain (mitochondria)
NET YIELD: 36 ATP (+2 to transport to mitochondria)
Cellular metabolism
a series of reactions to sustain cell life
Glycolysis
the chemical process to break down glucose into 2 pyruvic acid molecules
-10 steps
NET YIELD: 2 ATP
Citric Acid Cycle
-Requires O2
-Pyruvic acid from glycolysis is converted into acetyl CoA which enters C.A.C
-8 steps
-prepares hydrogen carrier molecules for entry into ETC
NET YIELD: 2 ATP
Electron transport chain
-requires O2
-series of reactions in inner mitochondrial membrane
-Major source of ATP (about 34 ATP)
NET YIELD: 36 ATP
Plasma membrane function
- form barrier for cell between ICF and ECF
- control movement of molecules
- joins cells
- ability to respond to changes in the environment
Plasma membrane structure
- most abundant are phospholipids
- -> non-polar tali and polar head
- proteins
- small amount of carbohydrates
- cholesterol
Phospholipids
- forms membrane
- barrier to water-soluble substances
- fluid-mosaic (not rigid)
Membrane Proteins
- Form channels across the lipid bilayer
- carrier molecules
- docking-marker acceptors
- membrane-bound enzymes
- receptor sites
- cell adhesion molecules (CAMs)
- help recognize ‘self’ in cell to cell interactions
Membrane Carbohydrates
- self-identity markers
- carbohydrate-containing surface markers are involved in tissue growth
Membrane Cholesterol
- between phospholipid molecules
- help fluidity and stability of cell membrane
- prevent fatty acid chains from crystalizing
Biological glue
Fibrin (helps with cell to cell adhesion)
Cell junctions
1) desmosomes
2) tight junction
3) gap junction
Desmosome
- spot rivets
- considerable to stretching
Tight junctions
- firmly bind cells
- seal off passageways between cells
- found in sheets of epithelial tissue
- prevent leaks in epithelial sheets
Gap Junctions
- small connecting tunnels (connexons)
- abundant in cardiac and smooth muscle
Unassisted membrane transport
- diffusion
- osmosis
Assisted membrane transport
- carrier-mediated transport (facilitated diffusion)
- facilitated transport
- active transport
- vesicular transport
Diffusion
-high to low concentration (concentration gradient)
Roles:
1) O2 and Co2 exchange in lungs and blood
2) movement across kidney tubules
Osmosis
-net diffusion of water DOWN its concentration gradient (higher to lower concentration)
Isotonic solution
solution outside and inside the cell is the same
Hypertonic solution
cell swells
Hypotonic solution
cell shrinks
facilitated diffusion
- energy free
- Higher to lower concentration
- requires a carrier molecule
active transport and types
- AGAINST concentration gradient
- needs carrier molecule
1) primary active transport (uses ATP)
2) secondary active transport (does not use ATP)
Primary active transport
requires the use of ATP
-low to high concentration
Secondary active transport
- indirect use of ATP
- latches onto primary active transport
Endocytosis
Cell taking in
- pinocytosis
- receptor-mediated endocytosis
- phagocytosis
exocytosis
Cell expelling
-provides a mechanism for secreting large polar molecules
Phagocytosis
cell ingesting another cell
Paracrine messaging
cell signaling
-A cell produces a signal to induce changes in nearby cells
Autocrine messaging
cell signaling
-cell secretes hormones that bind to that same cell and produces changes
Neurocrine messaging
1) neurotransmitter
2) neuromodulator (neuropeptides)
3) neurohormone
Cytokines
signaling cells that regulate immunity and inflammation
Hormones
1) hydrophilic
2) lipophilic
- chemical signals released into the bloodstream
Membrane potential and the role of the Na K pump
Makes a contribution to membrane potential because of the unequal transport of positive ions
polarization
any state when the membrane potential is other than 0mv
depolarization
the membrane becomes less polarized than at resting potential
repolarization
membrane returns to resting potential after having been depolarized
hyperpolarization
the membrane becomes more polarized than at resting potential
Neuron communication: two types of electrical signals
1) graded potential
2) action potential
Graded potential
- occurs in a small, specialized region of the membrane
- magnitude continues to decrease
Action potentials
- brief, rapid, large changes
- involves only a small portion of the total excitable cell membrane
- doesn’t decrease in strength
- threshold potential
Role of the activation and inactivation gates of the sodium channels
activation –> allows sodium into cell
inactivation –> (closed at rest) allows cell to become repolarized and return to resting potential
Refractory period and types
A period of time following an action potential
(decreased excitability)
1) Absolute
2)Relative
Absolute refractory period
- occurs in depolarization state and most of the repolarization state
- second action potential cannot be generated
- sodium gates = inactivated
Relative refractory period
- occurs in the last part of repolarization and hyperpolarization
- sodium gates closed
- second action potential possible with strong stimulus
- few potassium channels still open
Neuron structure
- Cell body
- Axon
- Dendrites
myelinated vs. unmyelinated fibers
myelinated: Myelin is composed of lipids saltatory conduction conduct impulses faster unmyelinated: contiguous conduction
Contiguous conduction
- Unmyelinated fibres
- action potential spreads along every portion of the membrane
Saltatory conduction
- myelinated fibers
- impulse jumps over sections of the fiber covered with insulating myelin
anatomy of synapse
- presynaptic neuron
- synaptic knob
- synaptic vessicles
- postsynaptic neuron
- synaptic cleft
Presynaptic neuron
brings the action potential
synaptic knob
contains synaptic vesicles with neurotransmitter
synaptic vesicles
stores neurotransmitter
postsynaptic neuron
neuron whose action potentials are propagated away from the synapse
synaptic cleft
space between the pre-and post-synaptic neurons
excitatory synapses
the presynaptic terminal increases the probability of the action potential of the postsynaptic terminal
inhibitory synapses
the presynaptic terminal decreases the probability of the action potential of the postsynaptic terminal
synaptic delay
the time it takes for a signal to be conducted across the synapse
neural summation
temporal and spatial summation
temporal summation
a high frequency of action potentials in the presynaptic neuron elicits postsynaptic potentials
spatial summation
the effect of triggering an action potential in a neuron from one or more presynaptic neurons.
effect of drugs (cocaine) on synaptic transmission
Blocks reuptake of neurotransmitter dopamine at presynaptic terminals (excess dopamine)
effects of the disease (Parkinson’s) on synaptic transmission
deficiency of dopamine in the basal nuclei, a region of the brain involved in controlling complex movements (rigid muscles and tremors)
effects of infection (tetanus) on synaptic transmission
Prevents release of inhibitory neurotransmitter GABA, affecting skeletal muscles (uncontrolled muscle spasms)
