Unit 2

How do different types of neurons work together to send and receive signals?

- Afferent meurons are sensory neurons (goes to CNS) - Interneurons connect afferent and efferent neurons in any way they come - Efferent neurons are motor neurons (away from CNS)

How does communication happen within the body?

- By passing an action potential through neurons and neurotransmitters through synapses. - Dendrite receives a stimulus. - Depolarization of cell membrane - Generation of the action potential. - Action potential moves down the axon. - Repolarization occurs. - Action potential arrives at the axon terminal. - Calcium channels open and calcium ions move into the neuron - The neuron makes and stores neurotransmitters in the vesicles. - Vesicles in the axon terminal fuse with the plasma membrane - Neurotransmitters are released into the synaptic cleft. - Neurotransmitters bind to receptors on the receiving neuron's membrane

What are the tests and procedures in a routine eye exam?

- Eye Dilation: your pupil in front of the eye has been opened using special drops. - Slit Lamp Exam: a magnified analysis of your eye from front to back. - Vision Screening

Pituitary gland (and Thalamus)

- base of hypothalamus - secretes hormones (Motor Control Receives Auditory, Somatosensory and Visual Sensory Signals Relays Sensory Signals to the Cerebral Cortex Controls Sleep and Awake States)

CNS

- composed of spinal cord and brain - sensory impulses go to it, and motor goes away from it. - supervisor of nervous system

Basic structure and function of a neuron?

- dendrite - cell body - axon - axon terminal Dendrite receives a stimulus, or action potential, then it moves down the axon and at the terminals, a chemical called neurotransmitters are released and they get picked up by the next neurons dendrite.

Gyrus

A convoluted ridge between anatomical grooves.

Dendrite

Any of the protoplasmic processes conducting impulse towards cell body.

Hormone

Any one of the many circulating chemical signals in multicellular organisms that interact with target cells to coordinate parts of the organism.

How can corrective lenses be used to refocus light and resolve myopia and hyperopia?

Corrective lenses work by modifying the path of the light as it approaches your eye such that between the artificial lens and the lens of your eye - the light focuses on the retina.

Hyperopia

FARSIGHTEDNESS (behind retina)

How and why does reaction time differ in reflex and voluntary actions?

If it is voluntary, the signal has to go to the brain and be processed, whereas if it a reflex, like touching your hand to a hot stove, then it doesn't have to take time to go to the brain, the spinal cord just tells you to take your hand off the hot stove. This is why the time differs, because it has to go to an extra place before reacting.

How does an error in the structure and function of the eye relate to disease or dysfunction?

If the eye is too long or to short, then myopia or Hyperopia can occur. If the cones are not properly receiving color, then colorblindness will ensue.

What factors impact our ability to react to a stimulus?

If the part of the body that is receiving a stimulus is injured it may not be able to move to react to the stimulus. And on the contrary, if you put your hand on a burning stove, then you will react even faster because sometimes it doesn't even go to the brain.

Action Potential

Momentary reversal in electrical potential across a plasma membrane occurs when cell is activated by stimulus.

Myopia

NEARSIGHTEDNESS (in front of retina)

How do the CNS and PNS work together to control the body?

Sensory information goes through the PNS to the CNS to relay that information, motor information goes from the CNS to the PNS to relay that information. One goes through the other to take control of the body.

Neurotransmitter

Substance that transmits nerve impulses across a synapse

Accomodation

The automatic adjustment of the eye for seeing at different distances. Changes in lens.

How does the eye perceive depth, color and optical illusions?

The combination of the visual images (from the left occipital and the right ociptial) is what allows us to have depth perception. Certain types of spatial arrangements and certain types of motion will cause the brain to misinterpret the information, creating an optical illusion. Color is perceived by signals from the cones in the retina.

How do hormones interact with target cells?

The hormone, since it travels in body fluids, touches many cells, but only interacts with the target cell. The target cell has a receptor on it that attaches the hormone to the cell so it can do it's thing.

Communication

The transfer of information from one molecule, cell, or organism to another, as by chemical or electrical signals or by behaviors.

What are ways communication occurs in machines and in the human body?

They both use electrical signals, in machines they are passes sometimes by wires, but in the human body they are passed down by neurons to and from the CNS.

How does the power of sight allow humans to communicate with the outside world?

They can see different things, dangers and good things, and colors and all sorts of things that make them aware of the world around them.

How do scientists determine which areas of the brain are associated with specific actions, emotions, or functions?

They can see what function a certain part of the brain may have because of an injury or disorder. Some scientists in the old days sent electrical currents to see what happened of one part of the brain was activated.

How do neurons convey information using both electrical and chemical signals?

They use the electrical signals to go down the cell axon and body, then release the chemical called neurotransmitters into a synapse, which triggers AP in the next cell.

How do humans communicate with the world around them?

They use the senses that they have to communicate and gather information from the world around them.

What does it mean to have 20/20 vision?

This means that the test subject sees the same line of letters at 20 feet that a normal person sees at 20 feet. 20/40 vision means that the test subject sees at 20 feet what a normal person sees at 40 feet.

What is visual perception?

Visual perception is one of the senses, consisting of the ability to detect light and interpret it as the perception known as sight.

How does what we see impact other human body systems?

What we see can send panic signals to our endocrine system and then have an effect on systems from there. and also if we see something we are scared of it can stop our breathing, make us scream, close our eyes and other things.

What is a hormone?

a hormone is a chemical signal found in multicellular organisms. interact with target cells and travel in body fluids.

Neurologist

a physician skilled in diagnosing and treatment of diseases of nervous system

Glucagon

a protein hormone that is secreted by the pancreas, that increases sugar content of blood by increasing breakdown of glycogen in the liver

Depth Perception

ability to judge distance of objects and spatial relationship of objects and distances.

PNS

all outside CNS does not include optic nerve

Ion

atom or group of atoms carrying pos or neg charge because of loss or gain of an e-

Reflex

automatic and often inborn response to a stimulus that goes to spinal cord then directly back out, often not passing to brain.

Gland

cell or group of cells that secrete hormones, remove materials from blood, alters those materials.

Brain Stem

composed of midbrain, pons, medulla oblongata, and connecting spinal cord with forebrain and cerebrum.

Cerebellum

coordination of muscles and equilibrium

Lens

curved piece of glass or plastic, used to focus light.

Astigmatism

defect of optical system causing rays of light to fail to meet in focal point, resulting in blurred and imperfect vision.

Lobe

division of body organ marked off by fissure on surface

How are electrical impulses created in the human body?

electricity created by reversal in charge.

Examples of endo- and exo- crine glands

endo - pituitary gland, thyroid gland exo - salivary glands, sweat

Hypothalamus

functions: - *maintaining homeostasis* - coordinating endocrine and nervous systems - secretes hormones - controls hunger and thirst

Endocrine gland

gland that produces endocrine secretions

Exocrine gland

gland that releases a secretion to canal or duct, salivary, sweat, etc.

Endocrine system

glands and parts of gland that produce endocrine secretions, help to control metabolic activity and include pituitary, thyroid, adrenals, etc.

Limbic System

group of structures (hippocampus, hypothalamus, amygdala) concerned with emotion and motivation

Myelin Sheath

insulating coat of of cell membrane from Schwann cells that is interrupted by nodes of Ravenier

How is light focused by the eye?

it goes through the cornea and the aqueous humor, between the iris, through the pupil, and to the lens, the light getting more and more compact as it goes through the uitreous humor and finally to the retina, where it is sent to the brain. the many substances it passes through, mainly the cornea and the lens are what focus the light.

Axon

long nerve cell process conducting impulses away from cell body

Insulin

lowers blood glucose levels.

What are consequences of miscommunication in the human body?

miscommunication in the human body can result in the body starting to attack itself, a person not getting enough of a hormone, or not feeling pain, any number of things can result from a miscommunication. MULTIPLE SCLEROSIS.

Neuron

nerve cell

Optic nerve

nerve that conducts visual stimuli to the brain

Iris

opaque muscle that contracts to let light in that has a pupil, it is colorful

Pupil

opening in iris admits light to interior of eye.

Cone

photosensitive receptor cells of retina for color vision.

Cerebrum

right and left hemispheres memory, learning, emotions, and other highly complex functions.

Rod

rod-shaped photosensitive receptors in retina responsive to faint light.

Retina

sensory membrane lines eye, has layers of rods and cones, that converts light to chemical and nervous signals for optic nerve.

Sulcus

shallow furrow on brain separating gyri.

Blind Spot

small circular area in retina where optic nerve enters eye that doesn't have cones or rods.

Phrenology

study of conformation of skull based on belief that it is indicative of mental faculties and character.

Refraction

the light is deflected from a straight path in air, to water or glass, where the velocity is different

How to the eye and the brain work together to process what we see?

the retina, which receives the focused light, has cones and rods which translate color and faint light to chemical and nervous signals so the the optic nerve, which connects to the brain, sends it to the occipital lobe and other parts to be processed into our comprehensible picture.

Synapse

the space where impulses pass from one cell to another

Reaction Time

time between beginning of application of stimulus and beginning of organisms reaction to it

Cornea

transparent coat of eyeball covers iris and pupil and admits light to interior.

How do feedback loops help regulate the action of hormones?

two types of feedback loops: positive and negative - If something get to high and needs to be lowered, then it is positive, and hormones will be triggered to lower it - If something gets to low, then it is negative and needs to be raised to hormones are triggered to raise it.

Occipital

which region of the brain controls sight

Cerebellum

which region of the brain controls the following functions: - equilibrium - balance - muscle tone - strength

Brain Stem

which region of the brain controls the following functions: - heart beat - breathing - level of consciousness - sleep

Parietal

which region of the brain controls the following functions: comprehension of senses, taste, spacial surroundings

Frontal

which region of the brain controls the following functions: -movement -problem solving -reasoning -personality

Temporal

which region of the brain the following functions: -language -hearing