Essay 2 Outline

I.

Introduction: your body is active during sleep and wakefulness, brain, eyes, and muscles

·        Sleep is the time the body can undergo repair and detoxification (1)

II.

          Brain: awake functions

• the human brain never decreases inactivity. Studies have shown that the brain is as active during sleep as it is when awake (17)
• Nerve-signaling chemicals called neurotransmitters control whether we are asleep or awake by acting on different groups of nerve cells, or neurons, in the brain (18)
• Neurons in the brainstem, which connects the brain with the spinal cord, produce neurotransmitters such as serotonin and norepinephrine that keep some parts of the brain active while we are awake (19)
• Other neurons at the base of the brain begin signaling when we fall asleep (20)
• The brain directs the things we choose to do (like walking and talking) and the              things our body does without thinking (like breathing). The brain is also in charge of   our senses (sight, hearing, touch, taste, and smell), memory, emotions, and personality. (46)
• Cerebrum- controls reading, thinking, learning, speech, and emotions (47)
• Cerebellum - The cerebellum controls balance and complex actions like walking and talking. (48)

• Brain Stem - It controls hunger and thirst. It also controls breathing, body temperature, blood pressure, and other basic body functions. (49)

                     Sleep functions

• activity in the cortex - the surface of the brain - drops by about 40 per cent while we are in the first phases of sleep (2)
• first stage: brain waves are small undulations (5)
• second stage: waves intersperse with electrical signals called sleep spindles - small bursts of activity lasting a couple of seconds which keep us in a state of quiet readiness (6)
• stage 2 sleep, our brain waves (fluctuations of electrical activity that can be measured by electrodes) become slower, with occasional bursts of rapid waves called sleep spindles. (24)
• stage three: waves continue to deepen into large slow waves. The larger and slower the brain wave, the deeper the sleep (7)
• In stage 3, extremely slow brain waves called delta waves begin to appear, interspersed with smaller, faster waves. (25)
• stage four: reached when 50 per cent of the waves are slow. not taxed mentally (8)
• By stage 4, the brain produces delta waves almost exclusively. It is very difficult to wake someone during stages 3 and 4, which together are called deep sleep. (26)
• stage five (REM): there is a high level of brain activity, helps consolidate memory and emotion, as at this point in sleep blood flow rises sharply in several brain areas linked to processing memories and emotional experiences. In areas involving complex reasoning and language, blood flow declines

III.

            Eyes: awake functions

• take in tons of information about the world around you — shapes, colors, movements, and more. (38)
• blinking: both a voluntary and involuntary action (39)
• step into bright light, the eyelids squeeze together tightly to protect your eyes until they can adjust to the light (40)
• eyelids shut automatically to protect the eye from possible danger (41)
• lacrimal glands, which make tears. Every time you blink your eye, a tiny bit of tear fluid comes out of your upper eyelid. (42)
• tears wash away germs, dust, or other particles that don't belong in your eye (43)

                      Sleep functions

• the movement of the eyes denotes the different stages of sleep (10)
• first falling into semi-consciousness, the eyes roll. But as we move into deeper sleep, rapid eye movement (REM) occurs when the eyes twitch and dart about (11)
• REM occurs within about 90 minutes of falling asleep and recurs about every 90 minutes throughout the night. It denotes a time when most dreaming is done (12)
• The first four stages of each cycle are regarded as quiet sleep or non-rapid eye move-ment (NREM). The final stage is denoted by rapid eye movement (REM) (4)
• During stage 1, which is light sleep, Our eyes move very slowly and muscle activity slows. (21)
• People awakened from stage 1 sleep often remember fragmented visual images. (22)
• stage 2 sleep, our eye movements stop (24)
•  

IV.

            Muscles: awake functions

• Animals use their muscular and skeletal systems for support, locomotion, and maintaining their shape(44)
• Rapid muscular contraction is important in generating internal heat, another homeostatic function. (45)
• muscles help keep you upright and standing tall. They also give your body the power it needs to lift and push things (37)
• the skeletal muscles work with your bones to give your body power and strength. In most cases, a skeletal muscle is attached to one end of a bone. It stretches all the way across a joint (the place where two bones meet) and then attaches again to another bone (36)
• SKELETAL: sometimes called striated muscle: voluntary muscles (34)
• CARDIAC: muscle that makes up the heart (31)
• heart contract to pump blood out and then relax to let blood back in after it has circulated through the body (32)
• like smooth muscle, cardiac muscle works all by itself with no help from you (33)
• SMOOTH: also called involuntary muscles — are usually in sheets, or layers, with one layer of muscle behind the other (28)
• can't control smooth muscles (29)

                           Sleep functions

• During stage 1, which is light sleep, muscle activity slows. (21)
• Though a person can change their sleeping position about 35 times a night, the muscles of the body remain relaxed. This gives the chance for tissues to be repaired and restored. (15)
• However, studies indicate that muscles might receive just as much relaxation and repair during simple rest periods and that a state of unconsciousness is not needed for this to take place. (16)
• the muscles of the body are relaxed to a point of virtual paralysis (13)
• stage four: 40% of the blood flow usually reserved for the brain goes to the muscles. (8)

V.

            Conclusion: Your body has set tasks for both sleep and wakefulness