Search results for: 'epithelial cells'

Watch Later 2:35

By: HWC, Views: 8193

• A single nervous signal releases Ca2+ ions into the sarcoplasm and initiates the contraction cycle. step 1. ATP hydrolysis • ATP provides the to move myosin molecules back into the energized configuration necessary to perform the power stroke. Step 2. Crossbridge attachment • Myosin...

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The Vestibular System

By: HWC, Views: 6938

The vestibular system has important sensory and motor functions, contributing to the perception of self-motion, head position, and spatial orientation relative to gravity. The function of the vestibular system can be simplified by remembering some basic terminology of classical mechanics. All ...

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Summary of female reproductive cycle days 1-28

By: HWC, Views: 8163

■ The first five days of the cycle include the menstrual phase. ■ Progesterone and estrogen levels are low. ■ Menses occurs. ■ GnRH pulses more frequently promoting FSH and LH levels to rise. ■ Primary follicles are stimulated to develop. ■ Days five through thirteen consist o...

Watch Later 3:31

Labor and Childbirth - The Three Stages of Labor: Dilation, Expulsion & Placental مراحل الولادة

By: HWC, Views: 8181

Regulation of labor and birth - effects of estrogen and oxytocin on onset of labor • Just prior to birth, high placental corticotropin-releasing hormone levels stimulate the production of more estrogen. • High estrogen levels overcome the inhibitory effects of progesterone on uterine sm...

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Role of transport in a cell

By: HWC, Views: 7876

Transport of chemicals across the plasma membrane provides the following functions: Importing molecules for the maintenance of metabolic processes. Exporting chemicals produced by the cell or waste products. Communicating with other cells, allowing for the generation and conduction of a...

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How to make cDNA Animation

By: HWC, Views: 2292

This animation shows how an mRNA transcript can be used to make a cDNA strand.

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Barriers - eye structures, digestive mucosa, respiratory mucosa & genitourinary mucosa

By: HWC, Views: 8038

• Eyebrows, eyelids, eyelashes and conjunctiva serve to trap microbes preventing their invasion. • Tearing (lacrimation) is a protective mechanism that washes away microbes that attempt to enter the eyes. • Salts, mucus, and lysozymes in tears neutralize substances and bacteria. �...

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Factors that affect conduction rates (myelination, axon diameter & temperature)

By: HWC, Views: 7869

• Several factors determine the rate of conduction of action potentials: • Myelination • Axon diameter • Temperature • The step-by-step depolarization of an axon is called continuous conduction and occurs along unmyelinated axons. • Neurons in the PNS have many axons that ...

Watch Later 2:55

How proteins function? How do proteins work?

By: HWC, Views: 7404

How proteins function is really about how proteins "do work" in cells. How do proteins work? Let's start thinking about protein function by looking at something important to you: your hair. Keratin is a structural protein that is composed of 2 intertwined or helical strands. Keratin is also f...

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