6th-Chapter 6: Lesson 2.4 Controlling and Regulating the Body

Last updated 6 months ago

37 questions

6th-Chapter 6: Lesson 2.4 Controlling and Regulating the Body

Last updated 6 months ago

37 questions

Draggable item		Corresponding Item
cerebrum		body system that allows people to think, use the senses, move, and maintain important body processes
brain stem		cell that is specialized to receive and send signals
nervous system		largest part of the brain, which interprets information from the sensory organs; controls muscle actions and is responsible for intelligence, memory, and personality
spinal cord		part of the brain that controls coordinated, smooth muscle activity
endocrine system		part of the brain that controls the heartbeat and breathing rate
pituitary gland		part of the nervous system that carries nerve signals between the brain and the body
thyroid hormone		body system that produces chemical messengers called hormones, which regulate body processes
cerebellum		master gland of the body, which releases hormones to control other endocrine organs
neuron		substance produced in the thyroid that increases the rate at which the body uses energy

The nervous system is organized into two parts. The first is the central nervous system (CNS), which includes the brain and the spinal cord. The second is the peripheral nervous system (PNS), which includes the nerves and sensory organs. A healthy nervous system allows people to think, perform tasks, and maintain important body processes

Neurons
Neurons are the building blocks of the nervous system. A neuron is a cell specialized to receive and send signals. Neurons make up the brain, spinal cord, and nerves. In addition to neurons, the nervous system has millions of other cells that protect and support them.
There are three types of neurons. Some neurons carry signals from the body to the CNS. These are sensory neurons. In contrast, motor neurons carry information from the CNS to the body. Motor neurons control the body’s glands and tell muscles to contract or relax. A third type of neuron is the interneuron. Interneurons carry signals between neurons.

Brain
The brain controls nearly all body functions. For example, to bend the knee, the brain tells muscles on the back of the thigh to contract. At the same time, the brain tells muscles on the front of the thigh to relax. The brain also stores information and makes sense of signals coming from the sensory organs.
The brain is protected by the bones of the skull. Under the skull, layers of tissues cover and also protect the brain. A fluid flows over the brain and cushions it.
The largest part of the brain is the cerebrum. The cerebrum performs important functions. It interprets information coming to the brain from the sensory organs as well as controls muscle actions. The cerebrum also is responsible for intelligence, memory, and personality.
The cerebrum is divided into two nearly equal halves—the left and right hemispheres. The halves are connected by nerves that allow them to communicate. The inner region of the cerebrum is called white matter. The outer, wrinkled region of the cerebrum is the cerebral cortex, or gray matter. The cerebral cortex is divided into lobes and each lobe has a different function (Figure 2.22).

Spinal Cord
The spinal cord carries nerve signals between the brain and the body (Figure 2.23). The spinal cord is protected by bones of the spine called vertebrae. Tissues and fluid also cover the spinal cord.
Many nerves run up and down the spinal cord. The nerves branch from the spinal cord and run to the left and right sides of the body. Some nerves control the muscles. Other nerves carry sense information from the sensory organs to the brain.
The spinal cord also controls some reflexes. A reflex is an automatic response to a sensation. For example, if extreme heat is sensed at the fingertips, the spinal cord sends a signal to arm muscles to contract and move the arm away from the source of heat. This response does not involve the brain. That is why a reflex can be so fast. This type of response helps keep the body safe from dangers in the environment.

Eye
The eyes and brain work together to make vision possible. The eyes detect light with nerve endings. Nerves then carry this information to the occipital lobe of the brain, which forms images from the information it receives. Numerous structures help the eye capture light and send signals to the brain.

The inner, back layer of the eyeball is the retina (Figure 2.24). The retina is made of nerve endings that are very receptive to light. These nerve endings allow the brain to see color, black and white, and shades of gray. In the center of the retina is an area rich in nerve endings. This area is responsible for forming sharp images.

The front of the eyeball’s surface is covered by the cornea. Light enters the cornea and passes through a lens. The lens focuses light on the retina. The iris, the colored part of the eye, lies in front of the lens, under the cornea. The iris appears round and has a black, circular opening called the pupil. The pupil allows light into the eyeball. The iris can change the pupil’s size. In bright light, the iris shrinks the pupil to let in a small amount of light. In darkness, the iris widens the pupil to let in more light.

The eyeball is protected by the bones of the skull. A strong tissue gives the eye its spherical shape. A firm gel fills the inside of the eye to help keep the eyeball’s shape.
In front of the eyeball are eyelids, skin-covered flaps that can close and protect the eye. Tear glands are located above each eye. The tears lubricate and clean the eye’s outer surface.

Ear
The ear has three main parts, and each serves a different, but important, role (Figure 2.25). The outer ear, called the pinna, is the large part of the ear that people can see. The main job of the pinna is to help bring sounds into the ear. Sounds then enter the auditory canal, the part of the ear that extends inward. Earwax is also produced in the auditory canal. This part of the ear also amplifies (increases the volume of) sounds so they can be clearly heard and interpreted.
After sound is gathered by the outer ear and sent through the auditory canal, it reaches the middle ear. The middle ear includes the eardrum, which vibrates when sounds reach it. This part of the ear also includes the following three small bones:
hammer (malleus)
anvil (incus)
stirrup (stapes)
The inner ear converts sound vibrations produced in the middle ear into neural impulses that the brain recognizes as sound. This part of the ear includes the cochlea, which is a spiral tube. The cochlea is covered with nerve cells, which pick up different vibrations. These vibrations are then sent to the brain through the auditory nerve. The inner ear also includes the semicircular canals, which are attached to the cochlea. These canals are filled with fluids that move when you move, helping you to keep your balance.

Endocrine System
The endocrine system produces chemical messengers called hormones, which regulate body processes. The organs that produce these hormones are part of the endocrine system (Figure 2.26). These organs release hormones into the blood, which carries them all over the body. Certain organs respond to certain hormones. They respond by growing or developing or by making other hormones and products.

Pituitary Gland
The pituitary gland is called the master gland of the endocrine system and is located beneath the hypothalamus in the brain. The pituitary gland uses hormones to control other endocrine organs. For example, the pituitary gland makes hormones that control growth, development, birth, puberty, and other activities. The pituitary gland itself is controlled by the brain’s hypothalamus.

Thyroid
The thyroid is a gland located on the front of the neck, just below the larynx. It makes thyroid hormone. Thyroid hormone increases the rate at which the body uses energy. This also controls the body’s temperature.

Parathyroid Glands
The parathyroid glands are four tiny glands located on the back of the thyroid gland. These glands make parathyroid hormone (PTH). The parathyroid glands raise the blood levels of calcium and phosphate. Calcium and phosphate are minerals important for bone growth and the growth of all the body’s cells.

Adrenal Glands

The adrenal glands are located on top of each kidney. These glands produce several hormones that control the blood levels of minerals and salts. Adrenal hormones also control how the body uses energy sources such as carbohydrates.During stress, the adrenal glands make adrenaline. Adrenaline prepares the body to cope with stress by increasing the heart rate and breathing rate. Adrenaline also increases blood flow to the muscles, heart, lungs, and brain. The adrenal glands also make cortisol, which prepares the body to deal with stress.

Pancreas

The pancreas is an endocrine organ as well as part of the digestive system. As part of the endocrine system, the pancreas makes the hormones insulin and glucagon. Insulin and glucagon have opposite effects on blood sugar. Insulin lowers blood sugar, and glucagon elevates blood sugar. Together, these hormones keep blood sugar at a healthy level (Figure 2.27). If they do not work properly, a person can develop the disease diabetes. Diabetes results in abnormally high blood sugar. Untreated diabetes leads to kidney and eye damage. Diabetes can also cause heart disease.

Ovaries and Testes
The ovaries and testes are part of the endocrine system as well as part of the reproductive system. The ovaries produce the hormones estrogen and progestin. These hormones regulate the sexual growth and development of females, female sex characteristics, and the female reproductive cycle.
The testes produce testosterone. This hormone controls the sexual growth and development of males and male sex characteristics.

6th-Chapter 6: Lesson 2.4 Controlling and Regulating the Body

6th-Chapter 6: Lesson 2.4 Controlling and Regulating the Body

Neurons

Brain

Spinal Cord

Eye

Ear

Endocrine System

Pituitary Gland

Thyroid

Parathyroid Glands

Ovaries and Testes

Which part of the nervous system includes the brain?

What does a healthy nervous system allow people to do?

What is the function of the peripheral nervous system?

The nervous system is organized into how many parts?

Neurons

What are neurons?

What do sensory neurons do?

What is the function of motor neurons?

Which type of neuron carries signals between neurons?

Brain

The cerebrum is responsible for all of the following functions EXCEPT:

The cerebral cortex is made up of:

Which part of the brain is responsible for memory?

What is the purpose of the fluid that flows over the brain?

Spinal Cord

What is the main function of the spinal cord?

What are reflexes?

What protects the spinal cord?

Why are reflexes so fast?

Eye

The area responsible for forming sharp images is located in the:

The colored part of the eye that changes the pupil's size is the:

The part of the eye that detects light with nerve endings is the:

The function of tear glands is to:

Ear

What is the main job of the pinna?

Which part of the ear includes the eardrum?

What is the role of the cochlea?

What is the function of the semicircular canals?

Endocrine System

What is the main function of the endocrine system?

Where are the organs that produce hormones found?

How do hormones travel throughout the body?

How do certain organs respond to hormones?

Pituitary Gland

Thyroid

Parathyroid Glands

The pituitary gland is located beneath the hypothalamus in the brain.

The pituitary gland controls growth, development, and puberty.

The thyroid gland is located on the front of the neck.

Thyroid hormone increases the body's temperature.

Ovaries and Testes

What hormones do the adrenal glands produce?

What is the function of adrenaline?

What is the effect of insulin on blood sugar?

What hormones do the ovaries and testes produce?

Which part of the nervous system includes the brain?

What does a healthy nervous system allow people to do?

What is the function of the peripheral nervous system?

The nervous system is organized into how many parts?

What are neurons?

What do sensory neurons do?

What is the function of motor neurons?

Which type of neuron carries signals between neurons?

The cerebrum is responsible for all of the following functions EXCEPT:

The cerebral cortex is made up of:

Which part of the brain is responsible for memory?

What is the purpose of the fluid that flows over the brain?

What is the main function of the spinal cord?

What are reflexes?

What protects the spinal cord?

Why are reflexes so fast?

The area responsible for forming sharp images is located in the:

The colored part of the eye that changes the pupil's size is the:

The part of the eye that detects light with nerve endings is the:

The function of tear glands is to:

What is the main job of the pinna?

Which part of the ear includes the eardrum?