• Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

Card Range To Study

through

image

Play button

image

Play button

image

Progress

1/137

Click to flip

Use LEFT and RIGHT arrow keys to navigate between flashcards;

Use UP and DOWN arrow keys to flip the card;

H to show hint;

A reads text to speech;

137 Cards in this Set

  • Front
  • Back
What are the main functions of the nervous system?
Integrating center for information coming into the body from the periphery or internally; sensation
Generation of movement
Regulation of many body functions
Locus of much of makes us human – thought, self-awareness
What is the central nervous system?
Brain + Spinal Cord
What is the peripheral nervous system?
The nervous system outside the brain and spinal cord

Carries information to and from the CNS to the periphery
Describe the somatic nervous system.
Voluntary nervous system
Afferent and Efferent nerves
12 pairs cranial nerves
31 pairs of spinal nerves
Describe the autonomic nervous system.
Involuntary nervous system
(Efferent nerves)
Sympathetic component - "flight or fight" increase heart rate
Parasympathetic - "rest and digest," decrease heart rate/ maintain homeostasis
What are afferent nerve cells?
They are sensory cells
- impluses from receptors to CNS to inform about the state of body interior and exterior
-Somatic (from skin, skeletal muscles or joints) or visceral (from organs with the ventral body cavity)
What are efferent nerve cells?
Motor nerve cells
-Conduct impulses from CNS to muscles and glands
Motor nerve fibers (both autonomic and somatic/voluntary)
What is a ganglion?
A mass of nerve cell bodies
Draw a nerve cell.
Include: dendrites, cell body, initial segment/axon hillock, axon, myelin, collateral
What kind of cells form myelin?
Oligodendrocytes (in brain and spinal cord -CNS)
Schwann cells in PNS
What is a synapse?
The anatomically specialized junction between two neurons where one neuron alters the electrical and chemical activity of another
What kinds of cells conduct action potentials most rapidly? Why?
Myelinated neurons... Nodes of Ranvier are the gaps between the myelin.
What is the role of spines on dendrites?
- Change shape and strenth of connection with other nerve cells
What are neuroligins and neurexins?
Cell adhesion molecules that form a trans-synaptic complex... changes linked to cognitive disease
How many cranial nerves are there?
12
What are the kinds of spinal nerves and what are they related to?
Cervical nerves (head, neck, diaphram, deltoids, biceps, wrist extenders, triceps, hand)
Thoracic nerves (chest muscles, abs)
Lumbar (legs)
Sacral (bowel/bladder, sexual function)
What is gray matter?
Nerve cell bodies
What is white matter?
Nerve cell axons
Contrast the autonomic and somatic components of the nervous system.
Somatic -- neuron goes straight from CNS to skeletal muscle
Autonomic -- series of neurons, with preganglionic fiber and postganglionic fiber
What neurotransmitter is released by preganglionic and postganglionic neurons in the parasympathetic nervous system?
Acetylcholine
What neurotransmitters are released by preganglionic neurons in the sympathetic division?
Acetylcholine
What neurotransmitters are released by postganglionic neurons in the sympathetic division?
Norepinephrine
Draw spinal nerve.
Included: dorsal root ganglion, gray matter, spinal nerve, dorsal root, ventral root
If you got a knife through the dorsal root only, what would happen?
You couldn't feel, but you still could move (dorsal is afferent, ventral efferent)
What are the kinds of gated channels in nerve cells?
- Voltage gated (change in response to voltage change)
- Ligand gated (change is response to binding by an ion)
- Mechanically gated
What is the resting membrane potential of most neurons?
For the purposes of this class -70 mV (inside relative to outside -
negative charge on inside)
What do Na+/K+-ATP-ase pumps do?
Moves 3 sodium ions out, brings in 2 potassium - maintains high intracellular potassium and low intracellular sodium
Uses ATP to power

1) Sodium channels open, sodium leaves
2) Causes potassium channels to open... then brings it back to original, causing sodium to go again
Describe action potentials in relation to sodium and potassium channels
There is a rapid opening of voltage-gated NA+ allows many NA+ to enter. Though K+ channels open more slowly, there are more of them, and also they close more slowly, so it ends up hyperpolarizing.
Be able to draw sodium/potassium action potentials.
Big overshoot depolarzing when lots of sodium ions come in (depolarizing), then potassium ions leave cell, hyperolarizes because those channels are slower to close

Axes: x time, y membrane potential mV
What is an action potential?
An all-or-none sequence of changes in membrane potential (positive feedback) - example is ion permeability due to operation of voltage-gated Na+ and K+ channels
What is a graded potential?
A change in membrane potential that is confined to a small region of the plasma membrane
How does action potential travel?
It is passed down through depolarization (like a burning fuse)
What is a saltatory conduction?
Action potentials jump from one node to the next as they propagate along a myelinated axon.
What do synapses look like?
Chemical synapses have a synaptic cleft and neurotransmitter diffuses across cleft to bind to the receptors on postsynaptic neuron.
What is EPSP and what is the main neurotransmitter?
Excitatory post synaptic potential
Glutamate
What s IPSP and what are the main neurotransmitters?
Inhibitory postsynaptic potential (GABA and glycine are the main neurotransmitters)
What makes an action potential happen in the post-synaptic neuron?
The membrane potential at the initial segment must reach threshold.
How much of body weight does muscle tissue represent?
About 40%
Where do motor nerve cells make contact with muscle cells?
At the neuromuscular junction
Draw a sarcomere.
Include thick filaments (myosin), thin filaments (actin), cross bridges (links), titin (structure spring), z-disc (made up of protein)
What happens when a muscle contracts?
Sarcomeres shorten when cross bridges (myosin heads) bind to actin. The cross bridge also binds at an ATP binding site. The cross bridge flex to slide actin. The myosin crossbridge is powered by ATP.
Describe the cross-bridge cycle.
1) The myosin-binding site on actin becomes available, so the energized cross-bridge binds.

2) The full hydrolysis and departure of ADP + P causes the flexing.

3) Biding on a "new" ATP t the cross-bridge uncouples the bridge

4) Partial hydrolysis of the bound ATP energizes or "re-sets" the cross bridge
What is tropomyosin?
In the absence of calcium, tropomyosin blocks the myosin binding site on the actin, preventing cross-bridge attachment. When calcium is present, it binds to troponin, pulling away the tropomyosin and allowing cross-bridge bonding to actin.
Draw a neuromuscular junction.
Include motor axon, axon terminal, end plate, t-tubules, sarcolemma (muscle membrane folds), ACh (Acetylcholine) vesicles, myofibril, sarcoplasmic reticulum,
What do action potentials cause acetylcholine to do?
They cause ACh to release into the junction.
What do t-tubules do?
T-tubules (transverse tubule) conduct electrical depolarization of the sarcolemma into the muscle cell interior.
How is calcium brought to muscles?
Passage of action potential along t tubules opens special voltage gated calcium channels, the "ryanodine receptor," on the sarcoplasmic reticulim. The DHP "receptor" senses the voltage, and causes the calcium channels to open. Calcium ions are released into the cytosol and bind to troponin.
Draw the graph of an isotonic twitch contraction.
Isotonic = same tension, length changes, muscle shortens

Axes of graph: x time, y length

Long latent period
Draw the graph of an isometric twitch contraction.
Isometric = same length, different tension, muscles aren't shortening.

Axes of graph: x time, y force
Draw a graph of total tension.
Include active tension (upside down parabola), passive tension (part of a curve going up), and combination

Axes of graph: x length (percentage of rest length), y force
Why don't muscles contract all the time?
The sarcoplasmic reticulum is full of calcium pumps -- the DHP receptors are essentially plugs for specialized calcium channels, and ryanodine allows calcium to come out.
Draw a frequency-tension relationship.
Include twitch, unfused tetanus, and fused tetanus, summation.

Axes of graph: x time (with arrows for points of stimuli, getting very close together at fused tetanus), y relative tension
What is a tetanus?
A maintained contraction in response to repetitive stimulation is known as a tetanus. With an unfused tetanus, the tension may oscillate while muscle fiber partially relaxes because of low stimulation. Fused tetanus has no oscillations.
Draw a length-tension relation.
Upside-down parabola (once it is at 100% rest length, reduces ability to make connections, so force goes down)

Axes of graph: x length (percentage of rest length), y force
Draw force velocity curve (aka load velocity curve).
Hyperbolic curve

Part until 0 is isotonic shortening, the rest is lengthening contraction (isometric)

Axes of graph: x load, y shortening velocity
What are the three types of muscle?
Skeletal muscle (striated), cardiac muscle, smooth muscle
How do smooth muscles contract?
With thick (myosin - based) and thin (actin - based) filaments
How are cardiac muscle cells connected?
Striated arrangements, electrically connected, ions can move from one membrane to another
What are 4 kinds of muscle design?
strap (muscle fibers parallel), fusiform (muscle at top, long tendon), unipennate (tendon at side), bipennate (fibers coming into tendon out an angle)
What are two basic kinds of muscles that work in antagonistic sets to refine movement and allow force generation?
Flexors and extensors
What is a motor unit?
A motor neuron and the population of muscle fibers (between about 10 and 100) that motor nerve innervates
What are factors determining muscle tension?
1. Tension developed by each fiber
a) Action potential frequency (frequency-tension relation)
b) Fiber length (length-tension relation)
c) Fiber diameter
d) Fatigue

2. Number of active fibers
a) Number of fibers per motor unit
b) Number of active motor units
What are the three muscle fiber types?
1) Slow oxidative fiber (very resistant to fatigue, sustain a contraction)
2) Fast-oxidative glycolytic fiber
3) Fast-glycolytic fiber (more tension)
Describe the example of fish muscle recruitment.
Red (slow oxidative) fibers are for slow steady swimming

White (fast glycolytic) fibers are for burst fast swimming, and are what we eat

They are intermixed
What is the size principle of motor unit recruitment?
Slow oxidative = low recruitment threshold
Fast oxidative glycolytic = intermediate
Fast glycolytic = high
Draw tetanic muscle tension resulting from the successive recruitment of the three types of motor units.
Base of SO, taller layer of FOG, high layer of FG on axes time v whole-muscle tension
What are the key contributions of Sir Charles Scott Sherrington?
1) reflex arc
2) coined term synapse
3) first to isolate single motor unit
4) categorized sensory receptors as interoceptors, exteroceptors, proprioceptors
Describe the neural components of the pain-withdrawal reflex of stepping on a tack.
Pain sensor afferents detect pain in foot and send action potentials via afferent neurons to the CNS. Interneurons in the cord activate muscles to lift the leg, and also muscles on the opposite side of the body to support body weight. Muscles move the foot away from the painful stimulus. Inhibit extensors, activate flexors.
What sense muscle length and force?
Acting on local reflex circuits and by relaying impulses to the brain
1) muscle spindles provide info about length
2) golgi tendons provide info about force
How does the muscle spindle sense muscle length?
It generates a burst of action potentials as the muscle is lengthened, and the shortened muscle spindle produces fewer action potentials.
How does the golgi tendon organ sense muscle force as stretch?
It senses force as stretch in the collagen fibers, and stretches the nerve cell membrane, which causes depolarization by mechanical stretch-induced opening of ion channels
Describe vastus lateralis function in running dogs.
Walk -- vastus lateralis hardly changes length
Trot -- vastus lateralis muscle lengthens (like a brake)
Gallop -- vastus lateralis is both a brake and a motor
How many different kinds of cells are there in the human body?
About 350 kinds
What are the four basic functions of cells?
Multiplication, movement, change character (differentiate), signal to other cells
Describe the processes of spermatogenesis and oogenesis.
Spermatogenesis: diploid cell goes through Meiosis I and Meiosis II to create 4 haploid cells

Oogenesis: diploid cell goes through meiosis I, leaving one diploid cell and 1 polar body. the new diploid cell goes through meiosis II (halted at metaphase until fertilization), then leaving 1 haploid cell and 1 polar body
When does fertilization occur?
12-24 hours after ovulation
When does the first cleavage occur?
About 30 hours after ovulation
What are the stages of cleavage in the first week?
2 cell stage
4 cell stage
Morula (12-32 cells)
Blastula (128 cells), around central cavity
Blastocyst (700-800 cells)
What does the embryoblast turn into? What does the trophoblast turn into?
Embryoblast - future organism
Trophoblast - supporting structures
When does the blastocyst implant into the uterine wall?
In week 2
Has about a 50% chance of making it
What layers does the embryoblast divide into? What do they become?
Epiblast: future embro
Hypoblast: yolk sac
What direction does the primitive streak form in?
From the caudal end to the middle
What is gastrulation?
Gastrulation is the formation of the three germ layers (ectoderm, mesoderm, endoderm) through a process of migration and differentiation. Also creates a gut tube (endoderm) and a central rod (notochord).
What is the notochord?
The stiffened rod of mesoderm, future "core" of axial skeleton.
Draw gastrulation.
Include epiblast, invaginating mesoderm cells, hypoblast, yolk sac
What are derivatives of the ectoderm?
Epidermis, nervous system, eyes, ears, nose
What are derivatives of the endoderm?
Digestive, respiratory, most of endocrine
What are derivatives of the mesoderm?
Skeletal tissue, muscle, circulatory, lymph, reproductive
What is neuralation?
The central plate of the ectoderm folds into a neural tube
What are somites?
Paired segments of mesoderm
What are homeobox (Hox) genes?
An array of 39 genes on 4 chromosomes that determine position and identity of somites
How many somites do we have?
About 42
But some species can have up to 300 (snakes!)
Draw the formation of a central body cavity (coelom).
Include neural tube, paraxial mesoderm (somites), somatic mesoderm, and splanchnic mesoderm
What is the phylotopic stage?
The very beginning with just basic structures where pretty much all animals look the same.
What is the blind watchmaker analogy? What are some solutions?
Critiques of evolution can be based on the idea that evolution is agentless (blind) and complex (like a watch), so without a guide, changes are like assembling a watch blind.

Solutions:
1. Evolutionary changes occurred with many, many intermediate steps.

2. The process permit change and complexity because there are many modules with many interactions.
What do somites (paraxial mesoderm) differentiate into?
Dermomyotome
Sclerotome
What kinds of cells does the neural tube send out? What do they become?
Upper (dorsal) cells become sensory neurons
Lower (ventral) cells become motor neurons
How are vertebrae formed?
Sclerotome condenses around notochord and neural tube
Notochord remains a gelatinous substance in the vertebral discs
What do epaxial and hypapaxial mean?
When muscles and nerves begin to subdivide
some go to back/dorsal side - epaxial
some for to front/ventral side - hypaxial
What are primitive fins?
Specialized flaps of the body wall
Hypaxial muscles split around fin to make elevators on top and depressors below

We still have those, too! Limbs are modified fins
How do limbs get patterned and organized?
The apical ectodermal ridge
"organizing center" - sends out signals that cause pattern of cell differentiation
What are neural crest cells?
Cells at the upper, lateral border of neural plate that differentiate and migrate into the mesoderm. They are amazing stem cells, and form much of the head.
What are branchial arches?
They were originally the gill apparatus... Then turned into lower jaw/mandible.

Branchial arch 1 goes from inner ear to lower jaw
Branchial arch 2 goes from inner ear to hyoid (top of "voicebox")
What does the endocrine system do? What does the paracrine system do?
Endocrine system: broadcast, fixed source to dispersed targets, coordination of physiology, integration of physiology and behavior, regulation of gene expression

Paracrine: Interstitial (between cells), rather than through blood
Describe peptide and protein hormones. Give an example of each.
Peptide: short amino acid chains, neurosecretion/cellular secretion, oxytocin

Proteins: long amino acid chains, glandular secretion, prolactin

Both:
coded in genome, membrane receptors
Describe steroids.
-Small, lipid soluble
- Dietary precursors
-Glandular secretion
-Cytoplasmic receptors
Describe thyronines.
-Small, lipid soluble
-Dietary precursors
-Glandular secretion
-Cytoplasmic receptors
Describe catecholamines.
-Small, water soluble
-Dietary precursors
-Membrane receptors
-Glandular neurosecretion
Describe cytoplasmic receptors.
-Steroids, thyronines
-Directly regulate gene expression
- Slower
-Combine with DNA to regulate transcription, etc
Describe membrane receptors.
-Proteins, peptides, catecholamines
-Regulate enzymes
-Faster
-Activates existing army of enzymes to respond on a short time scale
-Actions triggered by membrane receptors involve cascading pathways of enzyme activation or inactivation, amplifying the signal and changing the cell's biochemical activity.
What are the embryological origins of the pituitary gland?
Posterior pituitary pouches down from the brain and in an extension of the neural components of the hypothalamus.

Anterior pituitary is from an invagination of the pharynx called Rathke's pouch (from primitive mouth).
What does the posterior pituitary do?
Secretes peptide hormones like oxytocin into the blood stream directly from neurons projecting from nuclei of hypothalamus.

Two hormones are: oxytocin and vasopressin
How does the anterior pituitary receive signals from the hypothalamus?
Receives them in a tiny vascular bed known as the "hypophyseal" or "pituitary portal system"
What does CRH stand for?
Corticotropin releasing hormone
What does ACTH stand for?
Adrenocorticotropic hormone
What is cortisol?
Steroid hormone produced in the adrenal cortex.
Elevated cortisol stimulates the mobilization of stored energy and suppresses reproductive and immune function (low at night during sleep, high during the day). Also responds to stress.
Draw the hypothalamic-pituitary-adrenocortical axis.
Include neural inputs, CRH (in hypothalamus), ACTH secretion (in anterior pituitary), cortisol secretion (in adrenal cortex), negative feedback of high plasma cortisol to ACTH and CRH
What are cortisol levels like among people struggling from depression?
Cortisol levels are constantly high - it doesn't go down like it does in other people.
What is dexamethasone?
A synthetic analogue of cortisol that provides exogenous negative feedback to the hypothalamus.
Why does the blastocyst have to implant itself in the endometrium?
It's running out of food as it's growing.
Draw a summary of ovarian events during a menstrual cycle if fertilization does not occur.
Include follicular phase, luteal phase, menstrual proliferative phase, secretory phase, drawing of days, estrogen, progesterone.
How does RU486, the "abortion pill," work?
Blocks progesterone receptors.
Also stimulates smooth muscle contractions with prostaglandins.
Where is estrogen synthesized?
Before ovulation: granulosa cells
After ovulation: corpus luteum
Where is progesterone synthesized?
Mostly in the corpus luteum.
Describe the process of implantation.
The blastocyst pulls itself into the tissue of mother with dorsal side of embryo. Trophoblast forms lacuni (lakes/pockets) with maternal blood.
What is HCG?
Human Chorionic Gonadotropin

Secreted by trophoblast cells, very similar to LH, luteinizing hormone secreted from the mother's pituitary.
What is a sheep's placenta like?
The chorionic villi are like hands in a glove with counter-current diffusion that keeps it so mother is always giving to baby
What is a human's placenta like?
It's like a hand in a casserole dish. While counter-current benefits are lost, surface area is gained, so human placentas transfer much more glucose than that of sheep.

Hemochorionic
What are problems that result from the structure of placentas in humans?
Because of higher blood glucose levels: gestational diabetes
Because of raised uterine perfusion pressure: gestational hypertension, eclampsia
What triggers human parturition?
When baby can no longer get enough nutrition from mother to support brain growth so must depend on own fat reserves
What initiates contractions?
Prostaglandins
When does the adrenocortical axis have to do with childbirth?
When blood glucose levels are low, the fetus starts producing it's own ACTH. This causes it to produce cortisol. The cortisol has a POSITIVE reaction on the production of CRH in the placenta. The placenta secretes prostaglandins, which causes uterine contractions. When the baby his the cervix, the posterior pituitary secretes oxytocin, which causes further uterine contractions.
Why did the baby born at 12 months never initiate labor?
It was missing that part of the brain, so it was getting enough nutrition to keep what it had going.
What is the role of relaxin in childbirth?
Softens the ligaments of the pelvis
What is the role of oxytocin in childbirth?
Synchronizes smooth muscle contractions of the uterus
Where is HCG synthesized?
Trophoblast/placenta
What kind of placenta does a sheep have?
What kind of placenta does a human have?
Epitheliochorial placenta -- but we can just say counter-current
Hemochorial