canalicular period

Examples of canalicular period in the following topics:

• Development of the Respiratory System

  • Lung development can be divided into distinct stages: the pseudoglandular period, the canalicular period, and the terminal saccular period.
  • The pseudoglandular period (also known as the glandular period) spans weeks six to 16, during which time the developing lung resembles an endocrine gland.
  • Respiration is not possible during this phase and fetuses born during this period are unable to survive.
  • The canalicular period spans weeks 16 to 26, during which the lumens of the bronchi enlarge, lung tissue becomes highly vascularized, and respiratory bronchioles and alveolar ducts develop from the terminal bronchioles.
  • The terminal saccular period spans from week 26 to birth.

• Development of Hearing and Balance

  • Critical periods have been identified for the development of the hearing and vestibular system.
  • Critical periods have been identified for the development of hearing and the vestibular system.
  • Disruption of maturation during this period can cause changes in normal balance and movement through space.
  • Moreover, exposure to abnormal vestibular stimuli during the critical period is associated with irregular motor development.
  • First reports on critical periods came from studies of deaf children and animals that received a cochlear implant to restore hearing.

• The Action Potential and Propagation

  • First is depolarization, followed by repolarization and a short period of hyperpolarization.
  • A period of increased potassium permeability results in excessive potassium efflux before the potassium channels close.
  • The propagation of action potential is independent of stimulus strength but dependent on refractory periods.
  • The period from the opening of the sodium channels until the sodium channels begin to reset is called the absolute refractory period.
  • During this period, the neuron cannot respond to another stimulus, no matter how strong.

• Periodic Abstinence

  • Periodic abstinence refers to abstaining from sexual intercourse during the fertile days of a menstrual cycle.
  • Most menstrual cycles have several days at the beginning that are infertile (pre-ovulatory infertility), a period of fertility, and then several days just before the next menstruation that are infertile (post-ovulatory infertility).
  • For these women, the rhythm method formula incorrectly identifies a few fertile days as being in the infertile period.
  • This schematic of a typical female menstrual cycle shows that periods of ovulation are taken in account to be a period of abstinence in calendar-based contraception methods.

• Interactions of Skeletal Muscles

  • The time between the stimulus and the initiation of contraction is termed the latent period, which is followed by the contraction period.
  • Taken all together these three periods are termed a twitch.
  • The time between stimulation and contraction is termed the latent period.
  • Together these three periods form a single muscle twitch,

• Introduction to Pregnancy and Human Development

  • Pregnancy is the period of gestation from the fertilization of an egg, through development of a fetus, and ending at birth.
  • In women who have a menstrual-cycle length of four weeks, this is approximately 40 weeks from the start of their last normal menstrual period.
  • In many societies' medical or legal definitions, human pregnancy is somewhat arbitrarily divided into three trimester periods as a means to simplify reference to the different stages of prenatal development.
  • This staging method is used only for the first 56 days in humans (prior to the fetal period).

• Gastric Phase

  • The gastric phase is a period in which swallowed food activates gastric activity in the stomach.
  • The gastric phase is a period in which swallowed food and semidigested protein (peptides and amino acids) activate gastric activity.

• Fibrocystic Disease of the Breasts

  • It is characterized by noncancerous breast lumps in the breast which can sometimes cause discomfort , often periodically related to hormonal influences from the menstrual cycle.
  • Women with fibrocystic changes may experience a persistent or intermittent breast aching or breast tenderness related to periodic swelling.
  • Symptoms follow a periodic trend tied closely to the menstrual cycle.
  • Symptoms tend to peak immediately before each period and decrease afterwards.

• Anatomical Changes

  • Implantation bleeding (occurs at implantation of the embryo in the uterus during the third or fourth week after last menstrual period).
  • This can be caused by many factors, including irregular periods (quite common in teenagers), certain medications (not related to conceiving children), and obese women who disregard the pregnancy-related weight gain.
  • Most women feel more energized in this period.
  • This period of her pregnancy can be uncomfortable and cause symptoms like weak bladder control and backache.

• Breathing Patterns

  • Breathing patterns refer to the respiratory rate, which is defined as the frequency of breaths over a period of time, as well as the amount of air cycled during breathing (tidal volume).
  • The time period is variable, but usually expressed in breaths per minute because it that time period allows for estimation of minute ventilation.