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Cardiac conductile cells

By: HWC, Views: 6876

• In order for the heart to function properly, all of its cells must contract in a specific sequence. This sequence is determined by a pathway known as the conduction system. • Cardiac muscle cells have two attributes that enable the conduction system to work: • Connective. Action pot...

Definitions of stroke volume, preload definition & Factors influencing stroke volume

By: HWC, Views: 6454

• Stroke volume is directly correlated with cardiac output-the greater the stroke volume the greater the cardiac output. • Stroke volume represents the difference in the amount of blood between: • the volume in the ventricles at the end of diastole (end-diastolic volume EDV); • the ...

Red alga life cycle Animation

By: HWC, Views: 865

Life cycle of Porphyra. The most conspicuous part of this algal life cycle is the haploid gametophyte. This sheetlike form is collected and dried for use as nori, the wrapping for sushi. Gametes form in packets interspersed between vegetative cells near the sheet margins. The gamet...

Structures that affect circulation - venous return

By: HWC, Views: 6449

• 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...

Stroke volume - contractility definition

By: HWC, Views: 6262

Contractility is the forcefulness of contraction of cardiac muscle. • Inotropic agents are substances that increase or decrease contractility (and stroke volume). • Positive inotropic agents increase contractility and will increase stroke volume and cardiac output. • Negative inotropi...

Definition of heart rate

By: HWC, Views: 6744

• Heart rate is determined by the rate of depolarizations of the sinoatrial (SA) node. • Cardiac output is directly proportional to heart rate, the greater the heart rate the greater the cardiac output. • Changes in heart rate are associated with exercise, stress or injury. Nervous ...

Hormones and the menstrual cycle Animation

By: HWC, Views: 3550

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...

HIV replication/ Replication cycle of HIV

By: HWC, Views: 3789

Replication cycle of HIV, one of the retroviruses. The HIV virus is surrounded by a lipid envelope with embedded proteins. A coat of viral proteins surrounds two strands of RNA and the enzymes used during replication. The virus attaches to and enters the host cell. Viral reverse trans...

Carbon fixing adaptations Animation

By: HWC, Views: 328

Different plants trap carbon by different pathways. Most C3 plants evolved in moist, temperate zones. On hot dry days they close their stomata to conserve water and oxygen accumulates. Under these circumstances, the enzyme rubisco uses oxygen in an inefficient reaction that competes with t...