Circadian Rhythm Flashcards Preview

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Flashcards in Circadian Rhythm Deck (14):
1

What is required to see circadian rhythym?

Many samples over a long period of time

2

One cycle every year is called ___________.

Circannual

3

One cycle every 30 days is called ____________.

Circatrigintan

4

One cycle every 7 days is called ____________.

Circaseptan

5

One cycle every 24 hours is called ____________.

Circadian

6

Cycles that occur at a higher frequency than circadian are referred to as ____________.

Ultraradian (HR, BP, etc.)

7

What is a good example of a circannual disorder? What is the treatment?

  • Seasonal affective disorder (SAD)
  • Blast with a high intensity light (Phototherapy)

8

What time do most myocardial infarctions and strokes occur?

9am

9

Why do most myocardial infarctions and strokes occur around 9am?

Circadian Rhythm

  • That is when the ANS is most active and the following are at their peak:
    • Blood pressure
    • Heart rate
    • Vascular tone
    • Platelet aggregation
    • Blood coagubility
  • The following are at the least during this time of day:
    • Coronary blood flow
    • Fibrinolytic activity

10

What nucleus is responsible for the circadian rhythm?

Suprachiasmatic nucleus of (SCN) of the hypothalamus

11

What is the tract that gives input to the SCN nucleus?

  • Retino-hypothalamic tract
    • Also recieved input from thalamus and raphe nucleus of brain stem (SCN is composed of heterogeneous population of neurons)

12

What cells are responsible for SCN input? What neurotransmitter?

3% of ganglion cells in ganglion layer that have melanopsin (Layer 8)

A image thumb
13

What is the output of the SCN nucleus?

Direct connection to pituitary and pineal gland

  • Central sympathetic intermediolaterl cell column (IML) of the spinal cord → Adrenal gland → Body through hormones (glucocorticoids)
  • Central parasympathetic dorsal motor nucleus of the vagus (DMV) → Body (via CN X)

14

What is rheostasis?

When "homeostasis" is obtained when all of the biological rhythms in an animal are fluctuating normally