Unit 7
The Brain
Frontal lobe
Critical thinking
reasoning
judgement
personality
motor cortex
controls voluntary movement
Parietal Lobe
Sensory Cortex
Interprets what to do with 5 senses input
Speech
Taste
Temporal Lobe
Memory
Smell
Hearing
Ocipital Lobe
Vision
Corpus Callosum
Passes information from one brain half to the other
Cerebellum
Balance and Coordination
Brain Stem
Midbrain
Processing of visual and auditory data
Pons
Fine motor skills by connecting the motor cortex to the cerebellum
Medulla Oblongata: INvoluntary functions
Breathing
Heart beat
Blinking
Digestion
The Nervous System
Nerve Cell - “Neuron”
The nervous system is comprised of billions of neurons.
Neurons are the basic functioning units (building blocks) of the nervous system
They are specialized cells that receive and transmit information and regulate all body functions.
Stages
Impulse begins at dendrite
Travels through the axon to the axon terminal/nerve ending
Begins impulse in the next neuron
Nerve impulse
The electrical signal through the nerve cell
3 Stages
Polarized
Known as Resting
More Na+ ions on the outside of the membrane
POsitive charge on the outside of the neuron
Negative charge on the inside of the neuron
Depolarized
Stimulus cause the Na+ gate to open
The Na+ floods into the neuron
The next gate opens and Na+ floods in
The inside is now positive charge = More Sodium on the inside
The outside is now negative
This area is called the Action Potential
It moves as a wave down the neuron
Repolarized
After the action potential wave passes the neuron must reset with the Na+ on the outside.
Na+ gates close
The pump will push the Na+ out.
Synapse - a gap between neurons
The Action Potential reaches to the axon terminal
Vescles attach to the membrane
Release nerotransmitters across the synapse
NEurotransmitters attach to the receiving neuron’s receptors
All or none
Once the threshold is reached the action potential occurs on the receiving neuron
After neurotransmitters can
Return to the axon terminal to be reused on the next action potential
Broken down by enzymes
Parts of the Nerve Cell Summary
The nerves relate to thinking as they get information across to each other and spread it throughout the brain making connections along with way.
Evolution of the Nervous System
Simplest
Nerve net
Ganglion and Lateral nerve cords
Brain with ventral nerve cord
Brain with dorsal nerve cord
Complex
Increasing Complexity:
Brain development
Sensory organs
Phylum: Porifera - Pore bearing
Simplest animal
Lacks many systems - cells work independently
Many structures rely on the flow of water to function
Water flows in the pores and out the osculum circulating O2 and nutrients
Sexual: Hermaphrodite
Asexual: Broken pieces can regrow organism
Cnidaria
Simple Animal
Radial symmetry
Use stinging cells on tentacles to capture prey
1st to have nerve cells
Hydra
Nerve net: feel touch
When touched they will sting with specialized celled on the tenetacle
Digestion
One digestive opening = mouth
Gastrovascular cavity will digest the food
Waste exits the mouth
Bud is for asexual reproduction
Sexual = hermaphrodite
Digestive Systems
Planaria
Digestive: one opening
Mouth siphon in food particles that are spread through the gastrovascular cavid
No circulatory to spread the food so the GVC tract expands from head to tail
First Bilateral Organisms
Head like region
Nervous
Ganglia: cluster of nerve cells in the head region: 2 lateral nerves
Eyespot: detect light
Auricles: Chemical sensing cells
Circulator/Respiratory: None
Use a small flat body to transport material easily by diffusion
Excretory
Flame cell
Planaria Reproduction
Asexually: Fragmentation/Regeneration
Sexually: Hermaphrodites with External Fertilization
Digestive Advancements
Perifera = filter feeder
Cnidaria. Playhelmthes
1 Opening and GVC
Nematoda
2 opening and intestine
Mollusca - Chordata
Add enzymes and other organs
Ascaris Body Systems
Nervous
2 Nerve cord that run from head to tail
Digestive
2 Openings
Mouth —> Intestine —> Anus
Live in a place where the food is already broken down and they can continually eat
Reproduction
Separate sexes
Female: Larger
Male: Smaller with curl
Male will insert the penile spicules into the vagina and release the sperm = internal fertilization
Evolution of the Reproductive System
Asexual Reproduction
Advantages
Don’t need a mate
Make many offspring
Respiratory Systems
Diffusion
Small and thin to move oxygen/carbon dioxide from cell to cell
Must maximize the surface that gas exchange can occur
Moisture
Water in aquatic environments
Mucus for land environments
Gills
The higher the oxygen levels the higher the blood flow as water flows through the gills.
Lungs
Muscles that will expand and contract the lungs
Able to breathe in more air to get more oxygen
Evolution of the Circulatory System
Primitive Animals
Move materials by diffusion
They have to be small and thin to get materials from cell to cell
Open vs closed systems
Open
Mollusks and Arthropods
Have no blood vessels
The heart pumps and squirts blood into an open cavity
Collects in the gills/lungs
Gills/lung oxygenate the blood and returns it to the heart
May not get all of the organs with enough blood
Closed
Annelida and Chordata
Have blood vessels
Heart pumps the blood
Blood flows through larger vessels into smaller capillaries throughout the body
Blood returns to the heart by blood vessels
All area of the body would have capillaries to get the materials it needs.
Evolution of the heart
2 chambered heart: 1 atria and 1 ventricle
Ventricles pump blood to the gills to pick up oxygen and then it goes straight to the blood
Loses pressure in the gills and maintains low pressure throughout the body
3 Chambered hearts: 2 atria and 1 ventricle
Right atrium collects blood from the body
Left atrium collects blood from the lungs
Both atria dumps into the ventricle - mixing of the oxygenated and deoxygenated blood
Can maintain blood pressure
4 chambered hearts: 2 atria and 2 ventricles
Separates oxygenated and deoxygenated blood
More oxygen to the body = more energy production
