B9-B10 (human Reproduction + Nervous System) Flashcards
What is stimulus?
Changed in the environment
What does the nervous system do?
Detects and respond to changes in the environment (stimulus)
Avoid danger
Detect food
Learn from experience
What are receptors?
Receptors pick up stimuli
More receptors-> more sensitive
What are the sense organs?
Tongue, eyes, nose, ears, skin
What are the organs in CNS and what does the CNS do?
Brain and spinal cord
Processes and coordinates sensory data + sends out motor commands
What are the parts of the PNS and what does the PNS do?
Peripheral nerves (nerve-> bundle of neurons)
Takes information from the organs to the CNS + from CNS to effectors
Explain the pathway of electric impulses through the nervous system
Receptor (stimulus) -> sensory neurons -> brain -> motor neurons -> effectors (response)
What are reflexes?
Automatic and rapid response to stimuli
Often protect from danger and doesn’t reach the brain until after the reaction has happened
Describe the path of an electric impulse through the nervous system for a reflex
Stimulus -> receptors -> sensory nerves -> relay neurons (spinal cord) (info is relayed not processed because reflexes need to be quick) -> motor nerves -> effectors
What are the differences and similaires between voluntary and involuntary movement?
Voluntary:
Slow
Conscious thought
Passes via the brain
Majority of movement
Involuntary (reflex):
Quick
Relay neurons in spinal cord
Protect the body
Both:
Both use sensory and motor neurons
Both use receptors and effectors
Involves electrical impulses
Using a diagram name and describe the functions of each part of the eye
Lens
Magnifying glass (20% of the magnifying)
Focus on further and closer things
Focuses light in the retina
Ciliary muscles
Squeezes lens -> thicker and thinner
Pupil
Hole in the center of the eye
Light enters the eye
Cornea
Protects the eye
Magnifying glass (80% of the magnifying)
Usually clear and first place light enters
Iris
Controls the amount of light entering the eye
Ring of muscle around the pupil
Muscles in the iris:
Circular and radial -> antagonistic muscles
Bright light/pupil contract -> circular contract, radial relax
Dim light/pupil dilate -> circular relax, radial contract
Suspensory ligaments
Suspense the lens
Connects to ciliary muscle
Blind spot
All receptors in the retina connect to this point (means no receptors here -> cannot see -> brain fills in image)
Optic nerve
Sensory neurons that carry impulses to brain
Retina -> brain
Sclera
White outer layer
Maintain shape and protect
Retina
Layered brain tissue
Photoreceptors
Rod -> peripheral, motion, dim light
Cone -> middle, color (red, blue, green), details (bright light)
What does accommodation require to happen?
Lens must change shape to focus light differently based on if you are looking at a closer or further object
Create a diagram showing how light enters the eye when looking at an:
A) close object
B) distant object
Close:
Thicker lens
Light enter is wider
Relaxed suspensory ligament
Contracted muscle
More refraction
Distant:
Thinner lens
Light enter is thinner
Tight suspensory ligament
Relaxed muscles
Less refraction
Draw a diagram and explain what causes:
A) short sightedness
B) long sightedness
And how it can be corrected
Fixed by glasses by focusing the focal point so it lands on the retina
Short sightedness:
Light focuses too early (before retina)
Causes:
Long eyeballs
Thick lens
Fix:
Concave/diverging lense
Spreads light rays
Long sightedness:
Light focuses to late (after retina)
Causes:
Short eyeball
Thin lens
Fix:
Convex/converging lense
Brings light to a focus
What are hormones?
Produced by glands
Chemical messengers released into the bloodstream
Alters activity of target organs (later destroyed but liver)
What does adrenaline do and how is it made?
Responds to danger -> fight or flight
Adrenal gland (on top of the kidneys) -> affects multiple organs
Describe the hormone response pathway
Adrenal gland releases adrenaline -> adrenaline is transported in the bloodstream -> receptors detect adrenaline -> effectors respond to adrenaline
What are some examples of effectors ?
Heart, stomach, eye (iris), muscles, blood vessels, brain
What are the effects of Adrenaline and why do they happen?
Increased blood glucose
More respiration -> more energy
Increased blood pressure
Blood travels faster -> more oxygen, glucose, adrenaline, take away waste
Expanding air passages of lungs
Allows more oxygen to enter and more CO2 to leave -> more respiration
Enlarged pupil
More light enters through the pupil -> see better
Redistributes blood to muscle and vital organs
Helps them work efficiently
Compare hormone and nerve responses
Hormone response:
Chemical signal
Relatively slow
Released by glands
Travels in the bloodstream
Effector -> generally organs
Nerve response:
Electrical signal
Relatively fast
Triggered by receptors
Travel along neurons
Effectors -> generally muscles
What is negative feedback?
Change occurs in the opposite direction to bring conditions back to normal
What is homeostasis?
Mechanism to maintain a constant and stable and internal environment (37°C)