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Electrical Conduction System of the Heart

By: HWC, Views: 5637

Your heart is a muscle that works continuously, much like a pump. Each beat of your heart is set in motion by an electrical signal from within your heart muscle. The electrical activity is recorded by an electrocardiogram. known as an EKG or ECG. Each beat of your heart begins with an electric...

Phases of the ovarian cycle

By: HWC, Views: 7003

• The ovarian cycle is a monthly sequence of events, consisting of three phases: • Preovulatory • Ovulatory • Post ovulatory Preovulatory phase • prior to ovulation: Primary follicles develop into secondary follicles. • Follicular cells surrounding the primary oocyte In...

Embryonic development - Week 3

By: HWC, Views: 6677

Week 3 (gastrulation) • Three primary germ layers are formed which provide cells for organ formation in the following months. • These germ cell layers are formed by a process known as gastrulation, which involves rearranging epiblast cells. • As cells from the epiblast migrate, a fain...

Spermatogenesis Animation

By: Administrator, Views: 9890

Spermatogenesis is the process by which haploid spermatozoa develop from germ cells in the seminiferous tubules of the testis. This process starts with the mitotic division of the stem cells located close to the basement membrane of the tubules. These cells are called spermatogonial stem cells. T...

The Vestibular System

By: HWC, Views: 5919

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 ...

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

By: HWC, Views: 7108

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...

Introduction to Breast Cancer

By: Administrator, Views: 9287

Breast cancer is cancer that develops from breast tissue. Signs of breast cancer may include a lump in the breast, a change in breast shape, dimpling of the skin, fluid coming from the nipple, a newly inverted nipple, or a red or scaly patch of skin. In those with distant spread of the disease, t...

Medullary osmotic gradient: countercurrent multiplier, urea recycling & vasa recta countercurrent exchange

By: HWC, Views: 7344

▪ The primary cause of the medullary osmotic gradient is the active transport of solutes. • In the ascending limb of the loop, active transport of Na+ ions drives passive reabsorption of Cl- ions. • Addition of these ions to the interstitial fluid of the medulla increases its osmolarity...

Protein Structure - Primary, Secondary, Tertiary and Quaternary

By: HWC, Views: 6619

A protein's first order structure, or primary structure, begins with the amino acid sequence of the polypeptide chain. The 20 different amino acids can be arranged in an infinite number of sequences. For example, the hormone insulin, which regulates the uptake of glucose from the blood into ce...