Exam 3 Flashcards
When did earth form?
4.6 billion years ago (bya)
When did life first form/evolve?
- Shortly after
- About 3.8 billion years ago
When did life emerge from water?
?½ million years ago?
billion probably?
When did human emerge?
About 2 million years ago (just a handful of years ago)
Common Descent with Modification
- A principle of the theory of evolution
- Species undergo modification through successive generations
- Changes in species can lead to formation of new, separate species
Species
In its simplest sense, they are different kinds of organisms
- Individual of the same species share genetic similarity and can (potentially) interbreed
- there is no good species concept
Population
-All individuals of the same species occupying a specific area over a particular time
All species have…
- Descended from other species
- A common ancestor lies at the base of evolutionary tree
What is the meaning of life?
Fitness (a measure of the number of successful offspring you leave in the next generation)
-Successful reproduction (leaving behind copies of yourself, or more specifically your genes)
Natural Selection
- Darwin
- An agent of evolution (“agent” means “something that causes”)
- Another basic principle in the theory of evolution
- Process through which a trait (or character) that confers reproductive advantage to an individual spreads in a population over successive generations
Biotic Potential
- Most populations are capable of producing more offspring that can be supported by the environment
- Exponential growth
Process of Natural Selection
-More offspring reproduced than can be supported by the environment
- Within populations, there is variation of traits between individuals:
- some of this variation is heritable
- variation in physical, psychological (or physiological), or behavioral traits with a genetic basis that can be passed onto offspring
- Because of their particular traits, some individuals have higher fitness (leave behind more offspring) than other individuals lacking the traits
- Overtime, beneficial traits passed through the population
Natural selection requires what?
- Competition!
- During competition for resources, some individuals will have an advantage because of physical, physiological, or behavioral traits
- Genetic traits that provided an advantage will be spread within a population, but those that do not will be lost from the population
- Selection through this process will change a population’s phenotype over time
- Individuals do not evolve, populations do!
Evolution
-Any genetically-based change of phenotype in a population over successive generations
What is it that evolves?
-Populations!
Example of allele changes in frog populations
- In original environment, it’s one large population, so they could interbreed
- In environment where species are separated, then they eventually can’t interbreed anymore
- In the different areas, fitness was increased for individuals with coloration that better matched each environment.
Importance of evolutionary thinking?
- Species are not fixed entities, but instead are constantly undergoing modification and change
- Organism today descended from other varieties that existed before them
- Humans have descended from other organisms that existed before them
Author and information of author of natural selection book?
- Charles Darwin
- Book is on the origin of species by means of natural selection (1859)
- Developed existing ideas about descent with modification
- Acquired a large body of supporting evidence
- Perceived natural selection as the primary force driving descent with modification
Other guy who isn’t Darwin and info on him?
- Jean-Baptiste de Lamarck (1809, before Darwin)
- Evolution of acquired characters
- Believed over time, an organism could acquire enough changes that one species could diverge into two, but also believed organisms change form over generations through inheritance of acquired characteristics (which is very wrong; examples of gauges, giraffes, etc.)
- REMEMBER: ON TEST, HE WILL HAVE QUESTION LIKE THE ONE ON GIRAFFES, AND THE ANSWER WILL (MOST LIKELY) BE DARWIN’S THEORY
Five Agents of Evolution?
- Natural Selection
- Sexual Selection
- Gene Flow
- Genetic Drift
- Mutation
Where do traits come from?
Mutations!
Mutation (in terms of traits and evolution)
- It’s a change in DNA sequence
- The only means by which new genetic information is generated
- Most are detrimental or harmless, but rare few are beneficial to organisms’ fitness
- Beneficial mutations are the building blocks of evolutionary change
What is the importance of the opsin gene mutation in primates?
- Mutation that duplicated an opsin gene
- Eventually mutated enough to see more color
Gene Flow
- The movement of alleles from one population to another by migration
- Introduce “novel” alleles to a population from some other population
Genetic Drift
-Chance alteration of allele frequencies in a population (change in allele frequencies)
Types:
- Founder Effect
- Population Bottlenecks
- Inbreeding (not focusing on this)
Founder Effect
- Type of genetic drift
- New population is started by a few individuals that are not representative of genetic diversity in the original population
- Colonization of a new habitat by a few individuals that then give rise to a new population
- Founding individuals do not represent the total genetic variation in original population
- Ex: founder effect in red spotted toads
- Rapid range expansion with a series of founder events
- Leading to reduced genetic diversity
Population Bottleneck
- Type of genetic drift
- Follows substantial population decline
- Surviving individuals do not represent genetic diversity of the original population
- Survival during the decline is random
- Chance of surviving is random; not based on selection of any trait or characteristic (if it was, it would be natural selection – not bottleneck)
- Ex: Northern elephant seals
- Original population: had high genetic diversity →
- Hunting in late 1800s: genetically reduced populations →
- Survivors had little genetic diversity →
- The difference is reflected in today’s population
-*Look in Evolution Parts 1 & 2 Packet
Sexual Selection
- Differential reproductive success based on differences in the success of obtaining mates
- Female mate choice
- Nonrandom mating
- Ex. Guppy female picking long tail, heavy spotted males.
- Controlling access to mates
- Ex: great-tailed grackles; local version called boat-tailed grackle
How species come into being?
-Speciation
Allopatric speciation (“of other countries”)
- Occurs when the geographical range of a species is split into discontinuous parts by formation of barriers to gene flow
- Could still mate with them but don’t
- Hypothetical example of forest frogs:
- Populations become isolated in different areas
- If enough gene flow occurs, the population will remain genetically similar
- But if gene flow is lacking, populations diverge
- After time, if individuals from diverging populations can no longer reproduce, speciation has occurred
Reading Evolutionary Trees
- Example in Evolutionary 1 & 2 Packet
- Example using the evolution of terrestrial animals in the phylum: Chordata
- Evolution of terrestrial vertebrates
- Vertical distance represents time
- Ancestral Characters: Existed in the common ancestor
- Derived Characters: unique to taxa (group)
- Remember mammals did/do lay eggs! Platypus
Evolution of the Great Apes
- When we shared a common ancestor:
- About 12 million years ago with orangutan
- About 6 million years ago with gorilla
- About 4.5 million years ago with chimpanzees
- Chimpanzees are more closely related to us than to gorillas
Tissue
A group of cells of a similar type that work together for a common purpose
Four Types of Tissue?
- Epithelial
- Connective
- Muscle
- Nervous
Epithelial Tissue
-Covers body surfaces; lines cavities and organs
- Shapes:
- Squamous
- Cuboidal: can be simple (function = secretion) or stratified (function = protection)
- Columnar: simple (single layer; good for getting things in and out) or stratified
-Look at figure/graph in book
Connective Tissue Types
- Most abundant and has various forms
- Cells embedded in extracellular matrix composed of protein fibers and ground substances
- Extracellular = outside of cell
- Matrix - structure implying that it doesn’t mix, yet it works together
- Protein Fibers = soluble protein fibers
- Collagen - Strong, ropelike, withstands pulling
- Elastic - Contains coils, stretches, then recoils
- Reticular - Thin, networks of collagen
- Ground Substances = cell secretions
- Solid, gelatinous, or fluid
- Various Forms:
- Binds
- Supports
- Transports
- Stores Energy
-Come in 2 types: proper and specialized
Proper Connective Tissue
- Type of connective tissue
- Areolar
- Adipose
- Dense
Areolar
- Type of proper connective tissue
- widely distributed under skin, around organs, and muscles
- structure and cushions
- think about it looking like a net
Adipose
- (fat) found under skin, around organs
- energy storage, insulation, cushioning of organs
Dense
- tendons and ligaments
- function = attachment and movement
Specialized Connective Tissue
- Type of connective tissue
- Cartilage
- Bone
- Blood
Cartilage
- joint cartilage (lines bones)
- absorbs shock (disks between vertebrae)
- more flexible cartilage in ears and nose
Bone
- for structure, protection, and movement
- bones are alive!
- storage of lipids (yellow marrow) and minerals (calcium, phosphorus), and production of red blood cells (red marrow)
Blood (in terms of tissue)
- cells and cell fragments (platelets)
- fibers = soluble proteins (obvious when blood dries and forms clots)
- main function is transport (of oxygen, CO2, nutrients, etc.)
- Plasma = liquid matrix
- Look at table in book
Muscle Tissue
- Skeletal
- Cardiac
- Smooth
Skeletal
- type of muscle tissue
- found around bones
- voluntary contraction
- cylindrical, striated cells with many nuclei
Proteins: Actin & Myosin
-Allows for muscle contraction
Cardiac
- type of muscle tissue
- found only around heart
- wall of heart, pumps
- involuntary contraction
- branching, striated cells with one nucleus
Smooth
- type of muscle tissue
- found around intestines and urinary tubules
- walls of intestines, blood vessels, etc.
- involuntary contraction (constricts)
- nonstriated, one nucleus
Nervous Tissue
-Associated with nervous system – nerves, brain, spinal cord
- Cell Types:
- Neurons
- Neuroglia
Neurons
- They are nerve cells
- Generate and conduct nerve impulses
Neuroglia
-Provides nutrients, insulates, protects neurons
Organ
-Structure composed of two or more DIFFERENT tissues that work together
Integumentary System
- Skin
- includes sweat glands, oil glands, hair, nails
- large organ
For:
-Protection: of physical and chemical factors and pathogens (invasion)
- Limits water loss: keratin (keratinization)
- Makes you waterproof
- Temperature Regulation
- Excretion: of wastes
- Sensory: detection of external stimuli
Skin Layers
- Two layers:
1. Epidermis
2. Dermis
Epidermis
- Layers of epithelial cells
- Constantly shed and replaced
- Keratinized outermost are dead (waterproof)
Dermis
- Lower level of skin
- Dense, connective tissue
- Blood vessels, hair follicles, glands, nerves
Skin Color
- Two factors:
- Pigment:
- melanin – produced by melanocytes
- colors dependent on form of melanin produced: yellow-red or black-brown & size of granules
- Blood Flow:
- amount of oxygen level
- High O2 = ruby red
- Low O2 = deep red-bluish
Accessory Structures
- Hair = modified skin cells
- Nails = modified skin cells
- Glands = oil, wax, sweat
- Functions: insulation, protection, or sensory
Homeostasis of Body Temperature
- Maintenance of favorable (stable) internal conditions in the face of external conditions
- Organ systems interact to provide controlled environments for cellular functions
- Sensor (receptor) –> Control Center –> Effector
- Temperature controlled by hypothalamus – set point is 37 degrees C
- Skin receptors sense surface temperature
- Internal receptors monitor blood temperature
- Brain initiates mechanisms (stimulates effectors) that produce or conserve heat
- When set point is reached, sensors no longer send signals to the hypothalamus, so hypothalamus stop signalling effectors
- Thus, a negative feedback (just like thermostat at home)
Skeletal System
- Support
- Movement
- Protection
- Storage (of fat and minerals)
- Blood cell production
Compact Bones
- Dense
- Central cavity (in long bones)
- Contained in blood vessels, yellow marrow
- Covered by membrane: periosteum
- Contains blood vessels, nerves
-Yellow marrow
Spongy Bone
- Lattice-like structure: latticework of tiny beams
- Contains red marrow
Bone
-Hard and resilient
- Made up of matrix
- Bone is a connective tissue
- mineral salts: hardness from mineral salts
- calcium and phosphorus
-Elastic protein: resiliency from elastic protein collagen
Bone Structure
-Covered by membrane, periosteum
-Blood vessels, nerves
Associated with bone growth and repair
- Bone cells = osteocytes
- Bone is made of repeating units - Osteons which consists of bone cell called osteocytes
Osteoblasts
- Osteo = bone
- Blast = beginning bud
- Make bone
- Cells that create matrix by secrete proteins and minerals (know dominant minerals, like calcium)
- Related to osteocytes
- During development bones start as cartilage, over time osteoblasts convert this bone
- Some osteoblasts form a matrix around themselves and become osteocytes
Bone Remodeling
- Lifelong process of deposition and breakdown
- Renews bone, regulates blood, calcium, and other minerals
- Osteoclasts
- Osteoblasts
- Calcitonin
- Parathyroid hormone stimulates osteoclasts
Osteoclasts
- Cells that breakdown bone
- Releasing calcium and other minerals
Osteoblasts
- Secrete new bone matrix
- Removes calcium and other minerals
- Hormone regulation (from thyroid):
- Calcitonin stimulates osteoblasts and inhibits osteoclasts
- Parathyroid hormone (PTH) stimulates osteoclasts
Calcitonin
-Stimulates osteoblasts and inhibits osteoclasts
Osteoporosis
-Disorder that results in weak, brittle bones
- Bone remodeling problem
- Estrogen aids in remodeling process
- Calcium is needed
- Vitamin D is needed for calcium absorption
Bone Repair
- Occurs when bone breaks
- Bleeding: clotting – bleeding from blood vessels in bone and periosteum
- Fibroblasts: formation of callus – connective tissue cells ingrown inward from periosteum, forming a callus (mass)
- Secretion of cartilage: these cells transform and begin secreting cartilage
- Transformation of cartilage to bone: osteoblasts (from periosteum)
Axial and Appendicular Skeleton
- Axial = Head, neck, body
- Appendicular = Arms, legs
- Skull is NOT one bone
- 14 facial bones
- Rib cage: protect internal organs
- Sternum (breastbone)
- 24 (12 pairs) of ribs
- Vertebral Column
- Vertebrae - 26
- Pelvic Girdle
- 6 fused bones
- Protects internal pelvic organs
- Supports weight of vertebral column
Joints
-Bendable places where bones meet
- 3 Types:
- Fibrous Joints
- Cartilaginous Joints
- Synovial Joints
- Cartilage layers that allow sliding of bone
- Membranes and cells that secrete fluid
Fibrous Joints
- Immovable
- Ex: Bones in skull
Cartilaginous Joints
-Immovable to slightly movable
- Ex: In rib cage (it can expand and stuff)
- Vertebral column
Synovial Joints
- Freely moveable
- Ex: Knee
- Cartilage layers that allow sliding of bone
- Membranes and cells that secrete fluid
How many freely moveable joints to humans have?
-More than 30
Muscular System
- Humans have more than 600 muscles
- Excitable (respond to stimuli)
- Contractile
- Extensible (stretch)
- Elastic (return to original length/form)
Structure/General Characteristics of Muscles
- Bundles: bundles of bundles of bundles of bundles
- Inside bundles are muscle fibers = muscle cells
- Muscle cell consist of many myofibrils
- Striated - Alternating (light & dark) bands of actin and myosin filaments
- One muscle cell extends from stationary attachment to a movable attachment
- Muscles come in antagonistic pairs
- One muscle opposes the other
- Ex. Tricep and Bicep
Sarcomeres
- They are functional units of contraction
- Each muscle cell contains thousands of sarcomeres
- Made up of protein myofilaments: actin and myosin
Movement of Sarcomeres
- (Sliding filament model)
- Sliding of actin filaments across myosin filaments
- Requires ATP: restoring myosin filaments has ADP and P bound to its head
- Uses energy to get immediate energy
-Thousands of sarcomeres sliding = contraction
Motor Unit
- Nerve (motor neuron) and the muscle cells it stimulates to contract
- Strength of a muscle contraction involves recruitment of more and more motor units
- Motor neuron may affect only a few muscle cells or thousands
- Think of lifting chair vs. lifting soda can example
Why do we prep energy for muscles?
To save time/prepare for use in an instance
Difference between lifting a can of soda vs. chair?
Number of motor units needed to initiate it (contraction movement)
Skeletal Muscle Contraction
- Signal from nerve
- Calcium is needed for muscle contraction
- Power stroke (ADP & P) move off)
- Myosin reactivation uses ATP (energy)
Signaling (of muscle contraction)
- Step 1: Nerve impulse reaches the neuromuscular junction
- Step 2: Acetylcholine released into the junction
- Step 3: Acetylcholine binds to receptors on the plasma membrane of sarcomere, and electrochemical message is generated
- Step 4: Calcium ions released from the sarcoplasmic reticulum – contraction initiated
- LOOK AT BACK OF SKELETAL AND MUSCULAR SYSTEMS PACKET
Neuromuscular junction
Junction between nerve and muscles
Slow-Twitch Muscle Cells
- Contract slowly
- Richly supplied with oxygen (aerobic)
- Abundant mtDNA
- Deliver prolonged, strong contractions
Fast-Twitch Muscle Cells
- Contract rapidly
- Powerful, packed with more actin and myosin
- Less endurance (anaerobic)
Muscular Energy in Muscle Cells
-Energy sources for muscle cells contractions
- Stored ATP:
- about 6 seconds
- Stored creatine phosphate:
- molecule used to quickly recharge ATP:
- about 10 seconds
- Anaerobic respiration:
- About 30-40 seconds
- For short efforts, this pathway generates ATP from glucose stored in muscle cells faster than the aerobic pathway
- Aerobic Respiration:
- Lower levels of ATP production for long periods
Nervous System
-Central: brain and spinal cord
- Peripheral: nervous tissue outside CNS
- All other nervous tissue on the outside
- Carry messages to and from CSN
What is the basic unit of the nervous system?
- Neuron!
- nerve cell
Neuron (2?)
-Excitable cell: generate and transmit information
Three types of neurons?
- Sensory Neurons
- Motor Neurons
- Interneurons
Sensory Neurons
-Conduct signal towards CNS (to brain or spinal cord)
Motor Neurons
-Carry signals from CNS to an effector (muscle or gland)
Interneurons
- Found only in brain and spinal cord
- Interpret sensory signals, initiate response
Reflex Arc
- Dendrite collect incoming signal
- Cell body integrate incoming sigma and generate out gouging signal
- Axon pass…
- LOOK IN NEURONS PACKET
- Finger over flame thing
- It would be one motor unit
Structure of a Neuron
- Dendrites: Provide huge surface for receiving signals
- Cell Body: contains all the normal organelles (including nucleus)
- Axon: (nerve fiber) long extension down which a signal travels
- Axon Endings: transmit signal
- LOOK IN NEURONS PACKET
Information Flow Through Neurons
- Signal collection
- Integration of incoming signal and generation of outgoing signal
- Axon
- SIgnal passed to another nerve cell or to an effector cell
Myelin Sheath
- Plasma membrane of glial cell
- Insulates Axon: insulating outer layer of axon
- Nodes: gaps; nodes of ranvier (unmyelinated gap)
- Signal moves fast by jumping gaps (100x faster)
- Signal skipping over the cells
- Occurs mostly on neurons outside CNS
- Start of lost of myelin sheath = multiple sclerosis (MS)
- LOOK IN NEURONS PACKET
What’s a nerve impulse (or signal)?
Also talk a bit about “rest”
- Action Potential
- Electrical signal caused by Na+ and K+ ions crossing neuron’s membrane (entering or leaving the cell)
- At “rest”, the inner surface of membrane is more negatively charged than outer surface
- LOOK IN NEURONS PACKET
Maintaining Differences in Electrical Charge
- Unequal distribution of Na+ and K+
- Open ion channels
- Gated ion channels
- Sodium/Potassium Pump
- LOOK IN NEURONS PACKET
Resting Potential
- Unequal distribution of ions
- K+ concentration high on inside of cell
- Na+ concentration high on outside
- K+ tend to leak out, Na+ tends to leak in
- Cell uses energy for pumps to maintain or reset sodium/potassium balance (necessary balance)
Action Potential
-Neuron receives excited signal; charge difference across membrane reverses
- Resting state: cell is negative inside, positive outside
- Resting Neuron: plasma membrane is negative inside relative to outside
- Depolarization
- Repolarization
- Action potential travels along axon “like a wave”
- Pumps then redistribute Na+ and K+
Depolarization
-Signal causes Na+ gates to open, these ions rush into the cell, and interior of cell becomes positively charged
Repolarization
- Restoration of resting state
- K+ gates open, these ions rush out, returning interior of cell back to negative charge
More on Action Potential
- Bioelectrical signal
- Uses differences in Na+ and K+ concentrations to move signal quickly
- Signal strength threshold (all or nothing)
- Refractory Period (pumps reset ion concentrations)
- Sustained signals occur as impulses
- Increasing strength of stimuli will increase pulse rate, but only to a point, and the signal cannot be reversed
Restoration of Ion Distribution
- Sodium-potassium pump restores original distribution of ions
- LOOK IN NEURONS PACKET
Why don’t we have threshold closer to resting point?
- Because we’d have too many!
- Everything would cause movement
- He twitched and stuff
- LOOK IN NEURONS PACKET
Neuron to Receptor Communication
Synapse, NT, types of synapses
- Synapse
- Junction between a neuron and another neuron.
- One neuron talks to another neuron.
- Neurotransmitters
- Chemical that carry signals between neurons
- Excitatory Synapse – increase activity of postsynaptic cell and increases likelihood of AN ACTION POTENTIAL
- Inhibitory Synapse – decrease activity of postsynaptic cell and decreases likelihood of AN ACTION POTENTIAL
- Any given neuron may have THOUSANDS of excitatory and inhibitory synapses – combine effect determines whether an action potential is generated
- Some excitatory, some inhibitory; combined effect determines whether an action potential is generated
-LOOK IN NEURONS PACKET
Synapse
-Junction between a neuron and another neuron
Neurotransmitters
-Chemicals that carry signals between neurons
- Once used, neurotransmitters must be removed from synaptic cleft
- Have to be removed so the action is not constantly repeated.
- Removed by enzymatic removal (ex: acetylcholinesterase removes acetylcholine) OR
- Recycled: pumped back into presynaptic neuron for reuse
- Many different types of neurotransmitters
- Activity of any neurotransmitter is determined by presence of receptors on “receiving neuron”
Why might you want signals to stop firing?
-Pain relief!
Neurotransmitter Examples
- Serotonin:
- obsession, compulsion, memory
- Norepinephrine:
- alertness, concentration, energy
- associated with fight or flight response
- Dopamine:
- reward, motivation, pleasure
Complexity of Synapses
- Neurons are talking to other neurons (inhibitory and excitatory)
- Acetylcholine and norepinephrine act in both CNS and PNS
Major divisions of the Nervous System?
- Central Nervous System and Peripheral Nervous System
- (CNS has all three types of neurons)
-LOOK IN NERVOUS SYSTEM PACKET
Peripheral Nervous System
- Sensory Division
- Receptors to external stimuli
- Receptors in skin, muscles
- Receptors in internal organs
- sensory neurons that signal to CNS
- sensory neurons found here
- Motor Division - motor neurons: carry signals from CNS
- Includes Somatic NS and Autonomic NS
- Motor neurons found here
Somatic NS
- Senses information
- Allows voluntary movements
- Ex: standing in shade when hot
Autonomic NS
- Regulates involuntary and subconscious activities
- Ex: sweating to cool down
Brain – Cerebrum, Cerebral Cortex, and Cerebral White Matter
-Cerebrum: complex portion of brain, consisting of two hemispheres
- Cerebral Cortex:
- Grey Matter - thin outer layer
- Billions of nerve cells with unmyelinated axons and glial cells
- Cerebral White Matter:
- Beneath the grey matter
- Nerve cells with myelinated axons
- Communication between neurons in the brain and between brain and rest of body
What does myelination have to do with humans?
- Communication between neurons in brain and between brain and rest of body
- Bouncing information quickly!
Areas of Cerebrum?
- Frontal Lobe
- Parietal Lobe
- Temporal Lobe
- Occipital Lobe
Frontal Lobe
- Voluntary motor function
- Personality
- Speech
- Frontal lobotomies
Parietal Lobe
- Many sensory function
- Including taste
-Sits behind frontal lobe
Temporal Lobe
-Auditory and olfactory
Occipital Lobe
-Processes visual information
Cerebrum – Sensory and Motor Areas
- Primary motor area
- Located across frontal lobes
- Primary somatosensory area
- Located across parietal lobes
-Figure 8.5
Other divisions of the brain
- Cerebrum
- Brain Stem
- Cerebellum
- Thalamus
- Hypothalamus
- Limbic System
Cerebrum
- Voluntary movement
- Interpreting sensations
- Decision making
- Self-awareness
- Creativity
- Language
- Much of memory
- Part of us we think is us?
Brain Stem
- Midbrain: relays and integrates signals
- Pons: bridge between higher and lower brains
- Medulla Oblongata: autonomic centers for respiration, heart rate, and digestion
Cerebellum
- Coordinates voluntary sensory-motor movements
- Stores memory of “learned motor patterns”
Thalamus
- SAID HE DON’T CARE*
- Process sensory signals and relays information to appropriate higher centers
Hypothalamus
- Largely responsible for autonomic functions of homeostasis
- Heart rate, blood pressure, breathing rate, body temperature, hunger
Limbic System
- Complex set of structures including the amygdala and hippocampus and nearby structures
- Primarily responsible for our emotional life
- Important in the formation of memories
- Figure 8.6
Two Different Types of Brain Injury
- Acquired brain injury
- Traumatic Brain Injury
Acquired Brain Injury
- cerebrovascular accident: (“cerebro” = brain; “vascular” = blood vessels; “accident” = problem)
- Death of neurons from interruption of blood flow to a region of the brain
- Causes:
- Stroke – blood clots, fatty deposits
- Aneurysms - burst blood vessels
- Heart Attack
- Meningitis – infections of the meninges (membranes surrounding brain and spine)
- Substance Abuse – drugs that affect the brain are often neurotoxins that cause damage when dosage is high or repeated
Traumatic Brain Injury
-Damage to neurons or nerve connections from force (trauma)
- Causes:
- Automobile accident (half of all cases)
- Slip-and-fell (shower)
- Sports Injury
- Gun Shot
- Explosions (war)
Spinal Cord
- Transmits signals to/from brain
- Connects to medulla
-Reflexes: interneurons associated with reflexes
Reflex Arc
- Circuit of neurons in spinal cord pre-wired to respond to stimuli
- Important for speedy responses
- Major Components:
- Receptor –> Sensory Neuron –> Integration Center (Interneuron) –> Motor Neuron –> Effector
-Look at other reflex picture thing!
Autonomic Nervous System– Two Parts:
- Parasympathetic NS
- Sympathetic NS
Parasympathetic NS
- ”Resting-n-Digesting”
- Individual organ responses
- Direct blood to digestive tract
Sympathetic NS
- ”Fight-or-Flight”
- All effects at once
- Acts via adrenaline (epinephrine and norepinephrine)
Traits of muscles?
- Contractile
- Elastic
- Extensible
- Excitable
Which type of neuron carries information (signals) decided on by nerve cells in the brain or spinal cord to muscles or glands that can then respond?
Motor Neuron
Terms that can be used to describe the signal that travels along a nerve cell?
- Action potential
- Nerve impulse
- Electrochemical signal
What is a synaptic knob?
-The tip of an axon ending at the end of a neuron
A skeletal muscle can be best described as?
-Bundles of bundles of muscle cells working together
What is the name given to the connection between a nerve cell (motor neuron) and a muscle cell?
Neuromuscular junction.
If the inside of the neuron is negatively charged compared to the outside, the neuron is in the…?
Resting state
What part of a neuron receives information from other neurons or from the environment?
Dendrite
What is the name given to the molecules or chemicals that carry a nerve impulse (signal) across the synaptic gap between two neurons?
Neurotransmitter
What is the first energy source for muscle contraction at the cellular level?
ATP stores
Which nerve is responsible for integrating and interpreting sensory signals and determining an appropriate response?
Interneurons
A motor unit is a?
Motor neuron and all of the muscle cells it stimulates
Which muscle type might you want if you were in a long-distance, multi-day backpacking race in the mountains?
Slow-twitch muscles
In terms of nervous system processes, what is an effector?
A muscle or gland that responds to information from the nervous system.
Which part of a neuron is most closely associated with transmission of an impulse (signal) over long distances within the body?
Axon
What is the name given to the junction between two neurons?
Synapse
The movement of an electrochemical signal along the axon of a neuron is associated with which ion?
Potassium ion (K+) AND Sodium (Na+)
Term that best describes muscles that oppose one another?
Antagonistic
What is a neurotransmitter?
A molecule (chemical) released by a neuron that transmits a signal to an adjacent cell.
What is the sliding filament model?
A description of the actions of actin and myosin filaments that cause contraction of a sarcomere
A description of the actions of actin and myosin filaments that cause contraction of a sarcomere
Neurons
When homeostasis for body temperature is completely lost, a person?
Dies
What is the definition for an organ?
A structure composed of two or more different tissues that work together to perform a specific function.
Sometimes swabs are taken of the inside of the mouth for DNA sampling. What type of cell is being collected?
Probably epithelial cells.
Which type of muscle occurs in the walls of intestines and is associated with the movement of food within the digestive system?
Smooth muscle.
What are the three components necessary for control of homeostatic factors like maintaining body temperature?
- Some type of structure that detects changes in the internal or external environment.
- Some type of control structure that integrates information from the receptors or sensors and directs an appropriate response.
- Some type of effector (that is a muscle or a gland) that can bring about a necessary adjustment when directed to do so.
What type of connective tissue contains cells specialized for the storage of fat?
Adipose
What is the name given to a group of cells that work together for a common function?
Tissue
What type of tissue does skin contain?
- Epithelial
- Muscle
- Connective
- Nervous
- Skin isn’t any general type of tissue, but it does contain all of the types)
Bone and blood are both examples of which general type of tissue?
Connective
What is the primary (first order) division of the nervous system?
Central and Peripheral
Blood and alcohol level is…?
Dependent on more than simply the number of drinks consumed (on your size too)
Opiates are _________?
Natural or synthetic drugs that affect pain relief in major ways.
What is the primary advantage to a spinal reflex?
It allows for very fast responses.
When a person uses a psychoactive drug so much that they need the drug for their physical or psychological well-being, this person is said to be?
Dependent on the drug.
The hypothalamus is largely responsible for homeostasis. Therefore, this portion of the lower brain must be associated with?
The control of functions like heart rate, blood pressure, breathing, and body temperature.
Where would you find interneurons (aka “thinking cells”) other than in the brain?
In the spinal cord.
According to the text, what are the potential health related effects of chronic marijuana use?
- Respiratory problems
- Increases risk of cardiovascular problems and disease
- Lower testosterone levels in males (the major sex hormone)
What type of nerve cell processes information about pain coming from the foot and then produced an appropriate response that is then sent to an effector (in this case, ordering the leg muscle to contract)?
Motor neuron
What is the major (first order) division of the peripheral nervous system?
Sensory vs. motor
Drugs that alter one’s mood and behavior are called?
Psychoactive
You just finished running and your heart rate is fast and you are breathing hard. In what part of the brain are basic body functions, like heart rate, blood pressure, and breathing controlled?
Hypothalamus (and maybe medulla)
The reaction of the body to an emergency is controlled by the ______ nervous system.
Sympathetic
What are the main parts of the central nervous system?
Spinal cord and brain.
The primary functions of the spinal cord involve?
Reflex actions and communication between the brain and spinal nerves.
What is the primary function of the cerebellum?
Coordination of complex muscular movements.
Processes of how a psychoactive drug can alter communications across a synapse?
- Drug could fit into the receptors for the neurotransmitter, blocking the neurotransmitter, but not stimulating an effect
- Drug could increase the number of neurotransmitter molecules in the synapse, thus producing a greater effect
- The drug could act like a neurotransmitter, fitting into the receptors and producing the effect
When it takes increasing amounts of a drug to have the same effect, someone is said to be?
Tolerant
Which organ is responsible for metabolizing alcohol?
Liver
What portion of our brain is considered the center of our emotions?
Limbic system (which consists of several interacting structures)
Which drug is not a stimulant, and is surprisingly, considered a depressant?
Alcohol
Psychoactive Drug
- Natural or synthetic molecules that alter communication between neurons:
- Releases NTs
- /Stimulates/Inhibits NTs
- Delay Nt removal/breakdown
- Acts like a NT by binding to NT
- stimulate receptors on postsynaptic neurons
- Prevent NT action
- block receptors (prevent NT action)
Physical response to chronic use: Tolerance
- Def: progressive decrease in effectiveness of a drug
- Require more drug… longer/more frequent doses to produce the same effect
- Body tries to maintain homeostasis in the face of drugs
- Increases enzymatic production to more quickly breakdown the drug
- Decreases number of receptors on postsynaptic neurons
Dependency
- Physical changes to nervous system
- Drug is required by user for their physical or physiological well-being
- No longer able to produce “appropriate” or “normal” responses because of physical changes (in nervous system)
- Drug required to maintain level of “homeostasis”
- Withdrawal symptoms occur when drug use stop signs
Drugs that most quickly lead to dependency?
-They stimulate “pleasure” centers of the brain
- Main examples:
- Cocaine
- Amphetamines
- Morphine/Opiates
- Nicotine
Cocaine
-Increases residence time in synaptic gap of NT’s
- Dopamine - blocking reuptake
- associated with pleasure centers of the brain
- Norepinephrine - simulates (or stimulates?) release
- normally involved in fight-or-flight response
- Results in feeling of confidence, alertness, pleasure, and power
- Snorted, smoked, or injected
Positive effects of cocaine are short-lived and then?
- Lasts no more than 90 minutes
- Followed by a “crash”… feeling anxiety, depression, fatigue (opposite of what you feel while on it)
- Produces a “craving” for more cocaine
Cocaine Health Issues?
- Cardiovascular
- Increases heart rate, blood pressure, and interferes with nerves that regulate heartbeat
- Constricts arteries - increases blood pressure
- Regulation of heart – can result in heart attack or stroke
- Respiration
- Interferes with neurons controlling respiration
- As cocaine wears off, activity in respiration centers of brain become depressed – potentially causing respiratory failure
- Damaged nerves, membranes, blood vessels of the nose (repeated snorting)
Amphetamines
- Synthetic stimulants that interferes with reuptake and increases release of dopamine and norepinephrine
- Effects dopamine and norepinephrine
- Effects of can last for hours
- In low, controlled doses, prescription versions of these drugs increases alertness, concentration, reduced fatigue
Meth
- Street form of amphetamine
- Smoked (most common), ingested as pills, crushed then snorted, or injected
- Behavioral modification
- Prolonged use appears to have long-term negative consequences to nervous system
- Chronic meth users often suffer from impairments to memory and emotional centers of brain
- Induces euphoria, feelings of high self-esteem, increased libido, insomnia, mania
- Long-term and high doses: anxiety, paranoia, movement disorders, also hallucinations, and psychotic behavior
- (Plug reuptake pumps)
Hallucinogenic Drug
- Ecstasy
- A diverse array of drugs – similar effects (like mushrooms, LSD, etc.)
- Visual, auditory, or other hallucinations
- Ecstasy (MDMA) or for all hallucinogenic drugs Effects:
- Serotonin (sense of well-being)
- Acetylcholine promotes release of serotonin and dopamine
- Norepinephine
Ecstasy Physiological Effects
- Stimulant
- Causes HYPERthermia (increased body temp - heat stroke)
- Dehydration
- If water intake is increased substantially, sodium and potassium can become diluted. Sodium needed for action potential in neuron. Better to drink something with electrolytes (gatorade)
- Ecstasy pills/liquids often contain other drugs
- Effect is more meth-like
Ecstasy Long-Term Effects
- Degradation of dopamine/serotonin releasing neurons
- Chronic…?
Opioids
- Affects opioid receptors
- Produce “morphine-like” effects – pain relief
- Variety of drugs: morphine, codeine, oxycodone, hydrocodone, tramadol, and heroin
- Easily leads to addiction, physical dependence, thus withdrawal
- Respiratory distress (death)
-Fentanyl and carfentanil – extremely potent, thus dangerous
Alcohol
- Depresses (slows down) neuron activity in the brain (of ALL)
- Tends to depress inhibitory neurons quickest
- Excitatory neurons run amuck AT FIRST
- Release from inhibitory controls tends to reduce anxiety and creates a sense of wellbeing
Ethanol
- (Alcohol)
- The alcohol in every “alcoholic” drink – very small molecule
- Both water and lipid soluble (will enter cell very quickly; readily gets into cells)
- Standard “drink” = 0.5 oz of ethanol(/alcohol?)
- Intoxicating effects begins quickly as it is absorbed
- Absorption begins in the stomach
- Higher concentration = faster absorption (stronger the alcohol, faster you’ll get drunk)
- Food slows down absorption
Once a neurotransmitter is released into cleft, how do you stop it from working?
- Reuptake
- Enzymes
