Brain

Question 1

1 The composition of the central nervous system and the peripheral nervous system

Answer 1

Central Nervous System: Brain & Spinal Cord, body’s main information processing center
Peripheral Nervous System: All the nervous tissue outside the CNS, delivers information to the CNS and carries messages from the CNS to other organs through nerves

Question 2

1 The difference between a dendrite and an axon

Answer 2

Dendrite: fibers that receive signals and carry them toward the neuron’s cell body
Axon: fiber that carries electrical impulses away from the cell body and toward other cells

Question 3

1 What a resting potential is and why it is negative in neurons

Answer 3

Resting neuron stores electrical energy. The neuron’s plasma membrane separates ions located inside and outside the cell. Opposite charges are held apart and an electrical potential is created from the differences in the charges. A resting neuron is a very small battey, with a voltage of about -70 mV. The charge inside the neuron is negative compared to the charge outside the neuron. Resting potential is the voltage across the plasma membrane of a resting neuron

Question 4

1 In which direction ions flow in and out of a neuron’s channels (channels in the plasma membrane), and how the balance of ions returns to normal after sending a signal; know how a signal is received and transmitted

Answer 4

Sodium flows inside, Potassium flows outside
Specific proteins built into the membrane from areas of higher concentration to areas of lower concentration . The membrane has more K+ channels than Na+ channels. Positive charge exits the cell as K+ is faster than it enters as Na+ ions The unbalanced diffusion of positive charge is the main cause of the outside of the cell being positive compared to the inside

Question 5

1 How the peripheral nervous system receives a signal and what it does to transmit a signal to an interneuron in the brain in terms of ion concentrations and the depolarization of the plasma membrane

Answer 5

If a neuron is stimulated, the voltage across the membrane changes at the point of stimulation (depolarization: charge difference across the membrane decreases). Stimulation causes the membrane to become more permeable to Na+. Na+ are much more concentrated outside than inside. A neuron will “fire” if the stimulus is strong enough to depolarize the membrane to a certain level, called the threshold, which is normally about -50 mV. This change opens more channels with gates that only open when that particular threshold is reached. This stronger depolarization is called the action potential, and is the beginning of the nerve signal. The inside becomes positive relative to the outside. This initiates action potential.

Question 6

1 The difference between electrical and chemical synapses, including the role of neurotransmitters

Answer 6

Electrical Synapse: the action potential at the end of the axon directly causes an electrical change in the receiving cell
Chemical Synapse: the nerve signal must be transmitted across a tiny space called a synaptic cleft.
Chemical signal consists of neurotransmitters: consist of small, nitrogen-containing organic compounds

Question 7

1 The type of neurons that are used by the peripheral nervous system to detect signals from the outside environment

Answer 7

Sensory division

Question 8

1 The type of neurons that are used by the peripheral nervous system to delivering the response of the central nervous system to muscle and gland cells

Answer 8

Motor: carries message from CNS to muscle and gland cells.

Question 9

1 What the somatic and autonomic nervous systems do when they receive signals

Answer 9

Carry signals from the CNS to skeletal muscles

Carry signals to organs like the intestines, heart, and glands. Cause involuntary responses

Question 10

1 The differences between the sympathetic and parasympathetic parts of the autonomic nervous system

Answer 10

Sympathetic: increases the general level of activity in the body and makes more energy available. Prepares the body for intense activities that consume energy like running or taking an exam. Controls “fight or flight”
Parasympathetic: calms the body, return it to regular maintenance functions. Decreases your heart rate and glucose release. Stimulates your digestive system to continue breaking down food.

Question 11

1 What the cerebrum is and what each hemisphere controls

Answer 11

Largest & most complex part of the brain; divided into two halves/hemispheres.Left controls movement on the right side of your body, right hemisphere controls movement of the left side of your body. Left is logical, problem solving, and language. Right is creativity and imagination.

Question 12

1 What the cerebral cortex and corpus callosum are and what they do

Answer 12

Cerebral Cortex: outer region of the cerebrum, contains neurons and makes up 40% of the total mass. The cortex is divided into several lobes. Responsible for reasoning, mathematical abilities, language skills, imagination, artistic talent, and personality traits.
Corpus Callosum: The hemispheres are connected by a thick band of more than 100 million nerve fibers. It supports communication between the hemispheres.

Question 13

1 What the cerebellum is and where it is located

Answer 13

Coordination center for body movements. Receives information for sensory receptors regarding positions of body parts & evaluates this information. Then it sends a plan for coordinated movements backto the cerebrum.

Question 14

1 What the brainstem is, what its three parts are, and what it controls

Answer 14

Medulla Oblongata, Pons, Midbrain.
Filters information from the sensory and motor neurons going to and from the brain. Regulates sleep, controls breathing, helps coordinate body movements

Question 15

1 What the thalamus and hypothalamus are and what each does

Answer 15

Thalamus: middle of the brain, sorts information going to and from the cerebral cortex. It exerts control over what information goes from sensory receptors to the cerebrum byblocking some signals and enhancing others
Hypothalamus: regulates body temperature, blood pressure, hunger, thirst, and emotions. Control center of endocrine system.

Question 16

1 What causes long-term memory

Answer 16

Long term memory is enhanced by associating new memories with old ones. You have to make new connections to make long term memories

Question 17

1 What perceptions are

Answer 17

Meaningful interpretations of sensory data (seen in different ways)

Question 18

1 What detects pain in the brain, and where pain sensors are located

Answer 18

There are no pain receptors in the brain. They are in all other parts of the body

Question 19

1 What the difference is between chemoreceptors and photoreceptors

Answer 19

Chemoreceptors: sensory receptors such as those in your nose and taste buds that are sensitive to certain chemicals
Photoreceptors: in eyes, receptive to various wavelengths of light

Question 20

The four main lobes of the brain are:

Answer 20

Frontal Lobe, Parietal lobe, temporal lobe, Occipital lobe

Question 21

Explain what it means to say that a cell membrane has become “depolarized.”

Answer 21

If a neuron is stimulated (by a tap on the knee, for example), the voltage across the membrane changes at the point of stimulation. This voltage change is called a depolarization, because the charge difference across the membrane decreases (the membrane depolarizes). This occurs because stimulation
causes the membrane to become more permeable to Na+. Recall that Na+ are much more concentrated outside the cell than inside. As Na+ diffuse into the cell, the inflow of positive charge depolarizes the membrane.