Chapter 9

Front 1

Define Endogenous Circannual Rhythms ;

Back 1

Internal mechanisms that operate on an annual (yearly) cycle.

Front 2

Describe Endogenous ;

Back 2

From within.

Front 3

Describe Circannual ;

Back 3

About yearly.

Front 4

What do all animals produce?

Back 4

Endogenous Circadian Rhythms.

Front 5

Define Endogenous Circadian Rhythms ;

Back 5

Internal mechanisms that operate on a 24 hour cycle.

Front 6

What do these 24 hour circadian rhythms regulate?

Back 6

Regulates wakefulness and sleep as well as many other behaviors and functions.

Front 7

What are some of the functions of circadian rhythms?

Back 7

Frequency of eating and drinking, body temperature, secretion of hormones, urination, and sensitivity to drugs.

Front 8

Cycle differ between?

Back 8

Differ between people and lead to different patterns of wakefulness and alertness.

Front 9

What can identifying your endogenous rhythm for sleep and wakefulness help you identify?

Back 9

Your best time to study and sleep.

Front 10

Your endogenous rhythm changes as function of?

Back 10

Age.

Front 11

What is the purpose of the circadian rhythm?

Back 11

Is to keep our internal workings in phase with the outside world.

Front 12

When the human circadian clock has no external cue to set, what happens to it?

Back 12

It generates a rhythm slightly longer than 224 hours.

Front 13

What establishes our circadian rhythm?

Back 13

An internal biological clock.

Front 14

Define Zeitgeber ;

Back 14

German meaning "time giver", refers to stimuli that reset the circadian rhythm.

Front 15

Examples of Zeitgeber ;

Back 15

- Sunlight (primary zeitgeber), exercise, meals, arousal of any kind, temperature.

- Depression, irritability, and impaired job performances are effects of using something other than sunlight as a zeitgeber.

Front 16

Define Jet Lag ;

Back 16

Refers to the disruption of the circadian rhythms due to crossing time zones.

Front 17

Examples of Jet Lag ;

Back 17

- Stems from a mismatch of the internal circadian clock and external time.

- Results in sleepiness during the day, sleeplessness at night, and impaired concentration.

Front 18

When you travel west what happens to our circadian rhythms.

Back 18

It Phase-Delays.

Front 19

When you travel east what happens to our circadian rhythms.

Back 19

It Phase-Advances.

Front 20

Circadian rhythms remain?

Back 20

Consistent despite lack of environmental cues indicating the time of day.

Front 21

Is it difficult to force a change in our circadian rhythm?

Back 21

Yes.

Front 22

What fails to reset our biological clock?

Back 22

Alarm clocks, raves, and brain damage.

Front 23

What generates our circadian rhythm and what makes it so tough to change?

Back 23

- The suprachiasmatic nucleus.

- Genes that produce certain proteins.

- Melatonin levels.

Front 24

Define the Suprachiasmatic Nucleus (SCN) ;

Back 24

Is part of the hypothalamus and the main control center of the circadian rhythms of sleep and temperature regulation.

Front 25

Characteristics of the Suprachiasmatic Nucleus (SCN) ;

Back 25

- Located above the optic chiasm / part of the hypothalamus.

- Damage to the SCN results in less consistent body rhythms that are no longer synchronized to environmental patters of light and dark.

Front 26

What does the SCN generate?

Back 26

Generates the circadian rhythms in a genetically controlled, unlearned manner.

Front 27

What does a single cell extracted from the SCN and raised in tissue culture continue to produce?

Back 27

Produces action potentials in a circadian rhythmic pattern.

Front 28

What did a mutation in one gene cause on hamsters?

Back 28

Caused SCN to produce a 20-hour rhythm.

Front 29

What does Light do to the SCN.

Back 29

Light resets the SCN via. a small branch of the optic nerve known as the retinohypothalamic path that travels directly from the retina to the SCN.

Front 30

Define Retinohypothalamic Path ;

Back 30

A small branch of the optic nerve.

Front 31

The retinohypothalamic path comes from?

Back 31

A special group of ganglion cells that have their own photopigment called melanopsin.