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Structures that affect circulation - venous return

By: HWC, Views: 7561

• Venous return directly affects cardiac output. • Increased venous return leads directly to greater cardiac output whereas decreased return contributes to decreased output. • Venous return depends on: • Blood volume regulation by the kidneys. • Venous tone. • Skeletal muscl...

Embryonic development - Weeks 5 to 8

By: HWC, Views: 7822

• The second month of development is characterized by rapid development of the head and limbs as well as continued organogenesis. • During the fifth and sixth weeks growth of the brain, and therefore head, is rapid. • Hands and feets begin to form. • During week seven, even more deve...

Hormonal feedback loop components

By: HWC, Views: 7831

The endocrine system maintains many body conditions within normal limits with feedback loops. Each endocrine feedback loop maintains homeostasis using the following components: ■ Stimulus - a change in a body condition. ■ Production cell - an endocrine cell that produces a hormone after b...

Five phases of cardiac cycle & Atrial contraction

By: HWC, Views: 7760

1. Atrial contraction (atrial systole). 2. Isovolumetric (ventricular) contraction. 3. Ventricular ejection. 4. Isovolumetric (ventricular) relaxation. 5. Passive ventricular filling. Beginning of cardiac cycle • Prior to atrial contraction: • Atria and ventricles are relaxed....

Stroke volume - preload, sarcomere length and Frank -Starling law

By: HWC, Views: 7352

• Sarcomere length affects muscle tension and the force of contraction. • Increased muscle stretch (increased sarcomere length) at the beginning of contraction increases tension produced during the contraction. • A more forceful contraction ejects more blood, thus increasing stroke volu...

Hormones and the menstrual cycle Animation

By: HWC, Views: 4649

Feedback loops to the hypothalamus and pituitary gland from the ovaries during the menstrual cycle Animation for a step-by-step explanation. Production of a releasing hormone (GnRH) by the hypothalamus prods the pituitary's anterior lobe to release FSH and LH. In the ovary, FSH and LH stimula...

Cellular Respiration & Glucose Mobilization (Glucose transport & Phosphorylation of Glucose)

By: HWC, Views: 7523

Glucose is completely broken down into CO2 and H2O during the process of cellular respiration, which includes 3 stages: 1) glycolysis; 2) the Krebs Cycle; and 3) the electron transport chain. Glucose enters this energy yielding pathway of cellular respiration in the first stage known as...

Medullary osmotic gradient - influencing factors

By: HWC, Views: 8058

▪ Maintenance of fluid volume and composition, despite changes in water input and output, is crucial to a healthy life. ▪ Regulation of blood's osmolarity, or solute concentration, is a function of the nephron. • Normal osmolarity is maintained by the ability of the nephron to alter uri...

Types of antimicrobial substances (interferons & complement protein)

By: HWC, Views: 7752

• Found in blood and interstitial fluids. • Discourage microbial growth. • Include interferon and complement proteins. • Produced and released by virus-infected lymphocytes. • Enter new cells and inhibit viral replication. • Act against a large variety of viruses (non-speci...