1. Weird body facts
fly larvae helps to heal wounds quicker long ago, some doctors noticed soldiers that had maggots on their wounds healed quicker than those without maggots. maggots eat the dead skin cells and bacteria. maggot therapy (also known as maggot debridement therapy (mdt), larval therapy, larva therapy, or larvae therapy) is the intentional introduction of live, disinfected maggots or fly larvae into non-healing skin or soft tissue wounds of a human or other animal. this practice was widely used before the discovery of antibiotics, as it serves to clean the dead tissue within a wound in order to promote healing.

2. ?
Sulci -fissures between
convolutions of brain

3. Organization of the nervous system
Central Nervous System
Peripheral Nervous System
Brain
Spinal Cord
Somatic
Autonomic
The human brain is a 3-pound (1.4-kilogram) mass of jelly-like fats and tissues—
yet it's the most complex of all known living structures.
Up to one trillion nerve cells work together and coordinate the physical actions
and mental processes that set humans apart from other species.
Nervous System Tutorial:
Structures of the brain:
Parasympathetic
Sensory
Motor
Sympathetic

4. Vertebrate Nervous System
Two divisions:
Central nervous system (CNS)- act as a coordinating centre (brain & spinal cord)
Peripheral nervous system (PNS)- effectors, carry information to and from the CNS.
Further divided into
Somatic – control skeletal muscle, bones & skin
Autonomic – control internal organs of body
Sympathetic
Parasympathetic
Somatic Nervous System (SNS)
Sensory neurons that convey information from sensory receptors in the head, body wall and limbs to the CNS
Motor neurons from the CNS that conduct impulses to the skeletal (voluntary) muscles only.
Autonomic Nervous System (ANS)
Sensory neurons convey information from receptors in the viscera (internal organs), to the CNS.
Motor neurons then convey information from the CNS to smooth muscle, cardiac muscle, glands, etc.
Motor functions in the ANS are not normally under conscious control; they are involuntary.

5. Anatomy of a nerve cell

6. Two different types of cells
Anatomy of Nerve Cells
Two different types of cells
Glial (neurological cells; non-conducting, offer structural support and metabolism of nerve cells)
Neurons (functional units of nervous system)
Three groups
Sensory Neurons
Interneurons
Motor Neurons

7. Three types of neurons Sensory (Afferent) Neurons Interneurons
INPUT – from sensory organs to brain and spinal cord
Sense and relay information from environment to CNS
Located in clusters called ganglia
Interneurons
PROCESSING
Link neurons within body
Integrate and interpret sensory information and connect neurons to outgoing motor neurons
Motor (Efferent) Neurons
OUTPUT
Relay information to effectors, (muscles, organs, glands; effectors as they produce responses) away from the CNS

8. Relaying the signal
Messages move from dendrite, through the nerve cell body, to the axon
Axons are covered with a myelin sheath (insulation), made by Schwann cells which prevent loss of charged ions from nerve cells
Areas between sections of myelin are called nodes of Ranvier; nerve impulses jump from one node to another, speeding up messages

10. Neurilemma promotes regeneration of damaged axons
All nerve fibres found within peripheral nervous system contain a thin membrane called neurilemma which surrounds axon
Neurilemma promotes regeneration of damaged axons
Not all nerve cells contain neurilemma and a myelin sheath
Nerves containing mylenated fibres and neurilemma called white matter due to whitish appearance
Grey matter lack myelin sheath and neurilemma and do not regenerate after injury
Ganglia: Groups of neuron cell bodies that lie within the PNS
Not included with nerves since nerves only contain axons and dendrites

11. Multiple sclerosis – myelin sheath destruction

12. The REFLEX ARC
The simplest neural circuit is the reflex arc. Reflexes are involuntary. No brain coordination is used. 5 essential components:
Receptor
Sensory neuron
Interneuron (in spinal cord)
Motor neuron
Effector

13. REFLEX ARC

14.
Knee Jerk Reflex:

15. Homework Complete Move Fast! Poster lab write-up Read pg 354-360
Q’s #7, 9, & 10

16. Electrochemical Impulse
The Electrocardiogram (ECG) is used to diagnose heart problems.
The Electroencephalograph (EEG) is used to measure brain-wave activity
Action Potential – the voltage difference across a nerve cell membrane when the nerve is excited
Resting Potential – voltage difference across a nerve cell membrane during the resting stage (usually negative)
Unlike most cells, neurons have a rich supply of positive and negative ions inside and outside the cell
Neuron resting potential
Uneven concentrations of Na+ (outside) and K+ (inside) on either side of neuron membrane results in the inside of the neuron being 70 mV less positive than the outside

17. - 3 Na+ ions are actively pumped out while 2 K+ ions are pumped in.
A sodium-potassium pump maintains resting membrane potential after ions “leak” down their concentration gradient
- 3 Na+ ions are actively pumped out while 2 K+ ions are pumped in.
Video
Text Q’s for after video: 3, 4

18. ACTION POTENTIAL
action potentials – the movement of an electrical impulse along the plasma membrane of an axon.
that are abrupt, pulse-like changes in the membrane potential that last a few ten thousandths of a second.
Action potentials can be divided into three phases: the resting or polarized state, depolarization, and repolarization
The amplitude of an action potential is nearly constant and is not related to the size of the stimulus, so action potentials are all-or-nothing events.
See Figure 8-14 on page 357

19. Depolarization must be completed and the nerve repolarized before the next action potential can be conducted as nerves conducting an impulse cannot be activated until the condition of the resting membrane is restored
This time is called the refractory period (usually 1-10 ms)

20. Video and Tutorial

21. Action Potential

22. ION GATES CONTROL THE MOVEMENT OF IONS ACROSS THE CELL MEMBRANE.
The separation of electrical charges by the “polarized membrane” has the ability to do work, expressed in millivolts (mV).
Upon excitation, nerve cell membrane becomes more permeable to Na than K
Na ions rush into cell causing depolarization
Once voltage inside cell is +ve, then Na gates close
The sodium-potassium pump located in cell membrane restores condition of resting membrane by transporting Na+ ions out of the neuron while moving potassium ions inside the neuron in a ration of 3 Na+: 2K+ ions
ATP fuels the pump

23. Saltatory Conduction

24. All or none response
A nerve or muscle fibre responds completely or not to a stimulus.
Nerves have a threshold level…minimum level of a stimulus required to produce a response.

25. Homework Watch Nerve Impulse Animation and make notes
Synapses - Mouse Party Task: Due Friday June 3rd
Go to:
Explore the effects of any three of the following drugs on brain function in mice:
Heroine, ecstasy, marijuana, methamphetamine, alcohol, cocaine, LSD
In your own words, explain how the drug affects brain function and draw a labeled diagram of the synapse depicting the effects for each drug

26. Terminology Synapse Synaptic Cleft Synaptic Vesicle Presynaptic Neuron
Region at which neurons come nearly together to communicate. (neuron or effector organ)
Synaptic Cleft
Gap between neurons (at a synapse)
Impulses can not propagate across a cleft
Synaptic Vesicle
Packets of neurotransmitter in presynaptic neuron
Presynaptic Neuron
Neuron sending a signal (before the synapse)
Postsynaptic Neuron
Neuron receiving a signal (after the synapse)

29. Neurotransmitters 5 general criteria:
1) synthesized and released by neurons
2) released at the nerve terminal in a 'chemically identifiable' form
3) the chemical should reproduce the activity of the presynaptic neuron
4) can be blocked by competitive antagonist based on concentration
5) active mechanisms to stop the function of the neurotransmitter
Classical transmitters are small molecules (often amino acid based)
Non-classical transmitters can be peptides or even gasses

30. 5 Steps of Neurotransmission
1) synthesis of the neurotransmitter
precursors and enzymes should be in
the correct place
2) storage of neurotransmitter OR
precursor
often stored in presynaptic vesicles

31. 5 Steps of Neurotransmission
3) release of the neurotransmitter
generally by vesicle fusion
4) binding to target receptor
ionotropic receptors open ion
channels
metabotropic receptors modulate
other signals

32. 5 Steps of Neurotransmission
5) termination of the signal
active termination caused by
reuptake or chemical breakdown
*For e.g. acetylcholine is broken
down by . . .
passive termination uses diffusion

34. Types of Neurotransmitters
Acetylcholine
+ muscles, learning, memory
Serotonin (a derivative of tryptophan)
+ sleep, relaxation, self esteem, too little = depression, perception
Norepinephrine (aka noradrenaline)
+ stress and fight/flight response, sympathetic NS:+BP & heart rate
Dopamine
+ prolactin (milk production), involved in pleasure, movement
Endorphins
(-) pain, involved in pleasure
GABA (gamma aminobutyric acid)
(-) anxiety, too little in parts of brain can lead to epilepsy
Glutamate
Most common NT, memory, toxic

35. “FLIGHT OR FIGHT RESPONSE”
Sympathetic component prepares body for stress [neurotransmitter used=norepinephrine]
Diverts blood from internal organs to skeletal muscles, heart & brain
Parasympathetic brings things back to normal [neurotransmitter used=acetylcholine]
Work in conjunction/opposition to each other
Ex. “on” / “off” switches
Autonomic Nervous System -

37. You come across a bear on your walk to school…what happens?
Sympathetic nervous system does what?
Increases heart rate
Increases breathing rate
Dilates bronchioles
Dilates pupils
Inhibits digestion

38. Acetylcholine – make post-synaptic membrane permeable to Na+
Cholinesterase (enzyme)…breaks down Acetyltcholine...prevents constant depolarization

39. CENTRAL NERVOUS SYSTEM
concentrated in the anterior portion of most animals
brain is covered by meninges
three-layer protective membrane forms the blood/brain barrier
determines which chemicals will reach the brain
cerebrospinal fluid surrounds brain and spinal cord
acts as a shock absorber and a transportation medium of materials
carries nutrients to brain cells
relays wastes from cells to blood

40. The Spinal Cord
carries sensory nerve messages from receptors of brain and relays motor nerve messages to
muscles
organs
glands
interneurons are organized into nerve tracts which connect the spinal cord with the brain
dorsal nerve tract brings sensory info into spinal cord
ventral nerve tract carries motor info from spinal cord to peripheral muscles, organs, and glands

42. The Brain
comprised of three main regions
forebrain
midbrain
Hindbrain

43. Forebrain
contains paired olfactory lobes
receive info about smells
thalamus (below the cerebrum)
relay, consciousness, pain
hypothalamus (below thalamus) (temperature, water, hunger, thirst, sex drive);
direct connection between hypothalamus and pituitary connects nervous system with endocrine system
cerebrum (2 hemispheres connected by the corpus callosum, surrounded by cerebral cortex and divided into 4 lobes:
frontal- voluntary muscles, walking, speech, personality, intellect
parietal- touch, temperature awareness, emotion, interpreting speech
occipital- vision and interpreting visual information
temporal – vision, hearing, memory, interpretation of sensory information

44. The Brain

45. Midbrain relays information to sensory areas (connective)
temporal- vision and hearing, linked to memory
Associative cortex: conceptualization, planning, contemplation, memory.
Motor cortex: voluntary movement of skeletal muscles.
Sensory cortex: vision, hearing, smell.

46. Hindbrain Primitive, controls breathing, heart rate, blood pressure.
Main regions of hindbrain
cerebellum, pons, and medulla oblongata
Cerebellum
located immediately beneath two cerebral hemispheres
largest section of hindbrain
deals with coordination and muscle control.

47. Pons acts as a bridge. Medulla oblongata
Passes information between two regions of cerebellum and between cerebellum and medulla
Medulla oblongata
Acts as connection between peripheral and central nervous system
controls involuntary muscle action
diaphragm, heart rate, blood vessel dilation etc.
also acts as coordinating centre for autonomic nervous system.

48. Autonomic nervous system
Sympathetic NS – prepares body for stress
Parasympathetic NS – return body to normal
Check out table

49. Natural Painkillers
Endorphins bond to sites on pain receptor ganglia (Substania Ganglia…SG).
Opiates simulate natural endorphins (p. 437)
Heroin, codeine, morphine etc…must continue to take in order to keep working (addiction!)

50. HomeWork
Case Study

51. Quick quiz
Quizzes on a range of bio topics :)
Another good quiz
A virtual body