Question 1

The principle of __________ states that different body systems mature at different rates.

Accepted Answer

The principle of the independence of systems states that different body systems grow at different rates.

Question 2

The __________ system is composed of the brain and the nerves that extend throughout the body.

Accepted Answer

The nervous system is composed of the brain and the nerves that extend throughout the body.

Question 3

Like all cells in the body, __________ have a cell body containing a nucleus. But unlike other cells, they have the ability to communicate with other cells.

Accepted Answer

Neurons, like other cells in the body, contain a nucleus. However, neurons are unlike other body cells in that they communicate with other cells.

Question 4

At one end of a neuron is a cluster of fibers called __________; they receive messages from other cells.

Accepted Answer

The dendrites are a cluster of fibers located at one end of the neuron. The dendrites receive messages from other neurons.

Question 5

Neurons have a long extension called an __________, the part of the neuron that carries messages destined for other neurons.

Accepted Answer

The axon is a long tail-like extension that carries the message from the cell body to other neurons.

Question 6

Neurons send messages to other neurons by crossing a small gap known as a __________.

Accepted Answer

Neurons do not actually touch one another. They communicate with other neurons through neurotransmitters, which travel across small gaps, known as synapses.

Question 7

Neurons communicate by sending chemical messengers, __________, that travel across the small gaps known as __________, between neurons.

Accepted Answer

Neurons communicate with other neurons through chemical messages, known as neurotransmitters, which travel across small gaps, known as synapses.

Question 8

Messages are transmitted from one neuron to other neurons by means of chemical messengers called __________.

Accepted Answer

The chemical messengers that carry the message from one neuron to another are neurotransmitters.

Question 9

Although estimates vary, infants are born with between 100 and 200 __________ neurons.

Accepted Answer

Although estimates vary, infants are born with between 100 and 200 billion neurons.

Question 10

By adulthood, a single neuron is likely to have a minimum of __________ connections to other neurons, or other body parts.

Accepted Answer

In adulthood, a single neuron is likely to have a minimum of 5,000 connections to other neurons, or other body parts.

Question 11

The result of synaptic pruning is to allow established neurons __________.

Accepted Answer

The result of synaptic pruning is to allow established neurons to build more elaborate communication networks with other neurons.

Question 12

The rapid increase in the overall size of the brain during the first two years can be attributed to __________.

Accepted Answer

The axons of neurons become coated with myelin, a fatty substance that, like an electric wire, provides protection and speeds the transmission of nerve impulses.

Question 13

If a baby's experiences do not stimulate certain nerve connections, those connections are eliminated, which is a process called __________.

Accepted Answer

Infants form billions of new connections during the first two years of life, more than are necessary. If a baby's experiences do not stimulate certain nerve connections, those connections will be eliminated through synaptic pruning.

Question 14

In addition to growth in dendrites, the axons of neurons become coated with __________, a fatty substance that, like the insulation on an electric wire, provides protection and speeds the transmission of nerve impulses.

Accepted Answer

The axons of neurons become coated with myelin, a fatty substance that, like an electric wire, provides protection and speeds the transmission of nerve impulses.

Question 15

The upper layer of the brain is known as the __________.

Accepted Answer

The upper layer of the brain is known as the cerebral cortex.

Question 16

The cerebral cortex is responsible for __________.

Accepted Answer

The cerebral cortex, the upper layer of the brain and the largest structure in the brain, is responsible for higher-order thought processes.

Question 17

If a particular part of a young child's brain is injured, other parts of the brain can compensate. This reaction illustrates __________.

Accepted Answer

Plasticity is the degree to which a developing structure or behavior is modifiable due to experience.

Question 18

As a newborn, Li Chan went through periods in which her legs would jerk in a regular pattern every minute or so. This is known as a __________.

Accepted Answer

Newborns often jerk their legs in repetitive, cyclical patterns, known as rhythms.

Question 19

Six-week-old Nigel went through periods of alertness, fussing, and crying. These periods are referred to as __________.

Accepted Answer

In this example, the periods refer to the degree of awareness Nigel displays: alertness, fussing, and crying.

Question 20

Maryam often wished she could sleep like a baby until she had a baby. Aftab, her 1-month-old son, went through various stages of sleep ranging from quiet sleep to periods during which he was actively moving about and crying in his sleep. These periods are called __________.

Accepted Answer

The various periods exhibited by Aftab represent different states, or periods of varying degrees of awareness.

Quiz 5: Physical Development in Infancy