Biology: Ch 27 And 28 Nerves And Structure

Front 1

What are the body's levels of organization?

Back 1

1. Cells
2. Tissues
3. Organs
4. Organ systems

Front 2

Cell Level

Back 2

The first level of physiology is the cell. Cells are interlocked and help to coordinate the actions of neighboring cells

Front 3

Tissues

Back 3

A cooperating unit of many similar cells that perform a specific function

Front 4

Organs

Back 4

Several tissues that together perform a specific task

Front 5

Organ System

Back 5

Consists of multiple organs that together perform a vital body function

Front 6

Types of Cells

Back 6

Muscle Cells
Nerve Cells
Bone Cells
Blood Cells

Front 7

4 Types of Tissue

Back 7

Epithelial Tissue
Connective Tissue
Nervous Tissue
Muscle Tissue

Front 8

Epithelial Tissue

Back 8

Sheets of closely packed cells that cover the entire surface of your body and the lining of your internal organs

Front 9

Connective Tissue

Back 9

This is the “Glue” that holds together and supports other tissues.
Examples include ligaments, tendons, fascia, bone, cartilage.

Front 10

Nervous Tissue

Back 10

Forms the communication system that makes this behavior possible
Neurons: The basic unit of nervous tissue

Front 11

Muscle Tissue

Back 11

Organs that enable you to move, run and swim.
Muscles are composed of several different types of tissue, including connective tissue, nervous tissue, and muscle tissue
You have voluntary (those you can control) and involuntary muscles (those you cannot).

Front 12

Types of Organ Systems

Back 12

Skeletal
Circulatory
Respiratory
Nervous
Muscular
Digestive
Endocrine
Excretory
Lymphatic
Immune
Reproductive

Front 13

Homeostasis

Back 13

The ways in which your body maintain its internal stability.

Front 14

How is Homeostasis Accomplished?

Back 14

Thermally, by sweating or shivering.
Oxygen debt, by increasing respiratory and heart rate.
Hormones also contribute.
Interstitial Fluid facilitates the interaction between gases and liquids.

Front 15

Integumentary System

Back 15

Skin
Your skin has 3 layers:
Epidermis-made up mostly of dead skin cells.
Dermis-made up mostly of connective tissue.
Hypodermis-made up mostly of fat cells.

Front 16

Bones

Back 16

organs made up of living material: bone matrix

Front 17

Cartilage

Back 17

Is on the end of bones for cushioning

Front 18

Ligaments

Back 18

strong, fiberous connective tissue. Connect bones in joints together

Front 19

Tendons

Back 19

Strong collection of tissue that connect muscles to bones

Front 20

Joints

Back 20

Where bones meet and can be moved.
Types of Joints:
Ball-and-Socket - shoulder
Hinge - elbow

Front 21

Arthritis

Back 21

This is a group of skeletal disorders that involve inflammation of the joints

Front 22

Osteoporosis

Back 22

This is a bone disorder in which bones become thinner, more porous, and more easily broken.

Front 23

How do muscles work?

Back 23

By contracting!
Muscles can only contract, or relax.
To move an arm involves a contraction on a muscle that’s attached to a bone.

Front 24

The Structure of a muscle

Back 24

A Muscle Fiber is a long cell containing many nuclei.
Inside a Muscle fiber are bundles of structures called Myofibrils.
Each Myofibril is composed of many inter-connected units called Sarcomeres. This is the thing that actually contracts to make a muscle move.
Each Sarcomere is made up of a thin filament of protein called Actin and a thick filament of protein called Myosin. The interaction of these two proteins is what makes a Sarcomere work, and a muscle fiber to contract.

Front 25

Nrvous System Subsystems

Back 25

Central Nervous System
Peripheral Nervous System

Front 26

Central Nervous System

Back 26

The brain and spinal cord.

Front 27

Peripheral Nervous System

Back 27

the nervous tissue outside the CNS.

Front 28

Nerve

Back 28

one or more bundles of neuron fibers surrounded by connective tissue

Front 29

What happens when you sense something?

Back 29

The PNS receives information about an environmental change. This is called a stimulus.
The stimulus is carried by sensory neurons and/or sensory receptors.
The CNS interprets the information through a process called Integration.
Next, the CNS orders a response. Perhaps instructing a muscle to contract or a gland to secrete a hormone.
Let’s look at an example:

Front 30

Four Features of a Neuron

Back 30

1. A cell body.
2. Two types of fibers:
Dendrites, which receive signals and carry them toward the neuron's cell body.
Axons, which carry electrical impulses away from the cell body and toward other cells.
3. A Myelin sheath - a thick, insulating material found on the axons of many neurons.
4. Nodes - uninsulated spaces along axons

Front 31

Resting Neruron

Back 31

not yet transmitting a signal.
A resting neuron stores electrical energy.
A plasma membrane separates ions inside the cell from ions outside the cell.
Ions diffuse back and forth through the membrane through protein channels specific for each ion. If more positively charged ions exist on one side of the membrane than the other, this difference in charges produces potential energy since diffusion “seeks” to maintain homeostasis.
This potential energy can be measured as voltage, and is called “resting potential.”
Sodium ions (Na+) are more concentrated outside the neuron than inside.
Potassium ions (K+) are more concentrated inside the cell than outside

Front 32

Ion Channels

Back 32

Proteins act as channels for each kind of ion.
There are more K+ ion channels than Na+ ion channels. This causes the outside of the cell to be more positively charged than the inside.
The membrane also contains a sodium-potassium (Na+/K+) pump, that pumps ions back across the membrane.

Front 33

Triggering a Nerve Signal

Back 33

If a neuron is stimulated—by a tap on the knee, for example— the plasma membrane becomes more permeable to Na+ ions.
As Na+ ions diffuse into the cell, an electrical “Nerve Signal” is created.
However, a neuron will only "fire" if the stimulus is strong enough. This is called the threshold. When a the threshold of stimulation is reached, Na+ ion channels are opened as "gates,“ allowing a rush of additional Na+ ions into the cell.
This rush of ions is called an action potential, and is the start of the NERVE SIGNAL

Front 34

How is a Nerve Signal passed to another Neuron?

Back 34

The end of a neuron's axon has many fine branches with knoblike tips.
The junction between these knobs and another cell is called a synapse.
Synapses may be electrical or chemical.
In electrical synapses, the action potential causes a direct, electrical change in the receiving cell (in heart and digestive organs).
In a chemical synapses, the nerve signal is transmitted across a tiny space by a chemical called a neurotransmitter.

Front 35

The Peripheral Nervous System

Back 35

The peripheral nervous system (PNS) transmits signals to the central nervous system (CNS) for processing
The PNS also transmits responses from the CNS to the rest of the body

there are two sets of sensory neurons.
One set brings in information about the outside environment from the external sense organs.
Another set provides the brain with internal information about the body such as temperature, heart rate, and acidity level of the blood.
Both sets of sensory neurons can also provide the brain with sensations of pain, which is the body's warning that it may be suffering tissue damage.

Front 36

Somatic Nervous System

Back 36

Motor neurons carry signals from the CNS to skeletal muscles. Mostly voluntary (extending your hand for a handshake) but can be involuntary (pulling away from something sharp)

Front 37

Autonomic Nervous System

Back 37

Motor neurons carry signals to organs such as the intestines, the heart, and glands. Mostly involuntary

Front 38

cerebrum

Back 38

the largest and most complex part of the brain.
It is divided into two hemispheres.
The hemispheres are connected by a thick band of nerve fibers called the corpus callosum.

The left hemisphere of controls movement of the right side of your body.
The right hemisphere controls movement of the left side of your body.

Front 39

Cerebellum

Back 39

Located below the cerebrum near the top of the spinal cord.
Function is to coordinate body movements.
The cerebellum receives signals from the cerebrum indicating a need to move.
The cerebellum receives information from sensory receptors regarding the positions of different body parts.
The cerebellum evaluates this information and, within a few milliseconds, sends a plan for coordinated movements back to the cerebrum

Front 40

Brainstem

Back 40

Structure: This is the lower section of your brain.
Includes the medulla oblongata, the pons, and the midbrain.
Function:
To filter all the information from the sensory and motor neurons going to and from the brain.
To regulate sleep, control breathing, and help coordinate body movements.

Front 41

Thalamus

Back 41

Located in the middle of the brain.
Function
Sorts information going to and coming from the cerebral cortex.
Controls what information goes from sensory receptors to the cerebrum by blocking some signals and enhancing others.

Front 42

Hypothalamus

Back 42

Function: Regulates body temperature, blood pressure, hunger, thirst, and emotions.
Serves as control center of the endocrine system.
Serves as your "biological clock" by maintaining daily cycles such as sleepiness and hunger.

Front 43

Sensation versus perception.

Back 43

Sensory receptors detect stimuli and send the information to the CNS.
A “sensation” is an awareness of these sensory stimuli.
A perception involves the integration of new information

Front 44

Types of Sensory Receptors

Back 44

Pain Receptors detect pain

Thermoreceptors detect heat and cold.

Mechanoreceptors detect pressure and motion

Chemoreceptors provide a response to certain chemicals

Photoreceptors are receptive to various wavelengths of light. (vision)

Front 45

The Eye

Back 45

More than half of human’s sensory input is visual.
Millions of sensory cells receive light and send signals to the brain.
The eye's structure is the key to its function.
The Sclera is the outer surface of the eye made up of connective tissue.
The cornea is a transparent area of the sclera.
The Iris gives your eyes their color .
The pupil controls how much light reaches the interior of the eye.
The lens, whose shape is changed by muscles, focuses images on the retina, the inner surface of the eye.

Front 46

Smell

Back 46

Odors originate from molecules that enter your nose.
Chemoreceptors in your nose have specialized cilia coated with mucus.
Chemicals dissolve in the mucus and bind to receptor molecules on the cilia.
The brain integrates the signals, resulting in the perception of an odor.

Front 47

Taste

Back 47

Taste also depends on chemoreceptors.
Chemoreceptors are found in some of the 3,000 taste buds that line your tongue.
Taste is stimulated when dissolved chemicals bind to receptor molecules on your taste cells.
There are four basic human taste sensations:
Sweet, bitter, salty, and sour.

Front 48

Drugs

Back 48

A drug is any substance used to produce an effect on the body.
Drugs include chemicals used for medicinal purposes (aspirin), “social” drugs such as alcohol and tobacco, and illegal drugs such as marijuana and cocaine.
Certain drugs affect the brain by altering the way neurons communicate.

Front 49

Drug Effects

Back 49

1. Increase the rate at which neurons release neurotransmitters.
2. Slowing down the rate at which neurotransmitters are removed from the synaptic cleft.
3. Mimicking a neurotransmitter by binding to its receptor sites.

Front 50

Stimulants

Back 50

Stimulants generally increase activity in the CNS by affecting the release or removal of neurotransmitters.
Ex: Caffeine, Nicotine, Cocaine, Methamphetamine.
Chronic use of some stimulants can lead to violent behavior, confusion, and sleeplessness.

Front 51

Depressants

Back 51

Depressants often slow CNS activity.
Examples: Alcohol, tranquilizers and barbiturates (sedatives).
Effects include interference with coordination and judgment, possible liver and brain damage, cardiovascular disease, and several forms of cancer.

Front 52

Opiates

Back 52

Narcotics such as Morphine, codeine, and heroin are narcotics derived from the opium poppy.
Opiates mimic natural chemicals in the CNS and bind to their receptors.
Opiates feelings of euphoria, slow the brainstem's normal functioning, and block pain signals.
Most opiates are addictive. Tolerance and addiction to opiates, especially heroin, can occur quickly, and withdrawal symptoms can be extremely painful.

Front 53

Hallucinogens

Back 53

Hallucinogens cause the user to see, hear, and perceive things that do not exist.
Some hallucinogens are natural substances, such as certain chemicals from psilocybin mushrooms and peyote cactus.
Other hallucinogens (LSD) are synthetic.
These drugs are illegal and very dangerous. The hallucinations can cause confusion and panic that can lead to severe injuries.

Front 54

Inhalants

Back 54

Inhalants include vapors of certain substances
These substances include volatile solvents, aerosols, certain gases, and nitrites.
Short-term effects of inhalant use include slurred speech, clumsiness, and increased heart rate.
Long-term effects can include damage to major organs, including the lungs and liver.

Front 55

Other Drugs

Back 55

Ecstasy is a synthetic drug called Ecstasy with stimulant-like effects (increased energy level) and hallucinogen-like effects (such as an exaggerated emotional attachment to other people).
Long term effects can include blurred vision, memory loss, and lingering paranoia. Long-term use also cause changes to the brain that may interfere with its functions.
Marijuana contains over 400 chemicals. The main mind-altering ingredient is THC (tetrahydrocannabinol). Marijuana causes many changes in the brain, including problems with memory and learning, distorted perceptions, loss of coordination, and anxiety.