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Body plan of euglena Animation

By: HWC, Views: 2046

Euglenoids are single-celled organisms that live in lakes and ponds. A contractile vacuole pumps out the water that diffuses into the cell from its hypotonic surroundings. The body is covered by a translucent pellicle composed of flexible strips of a protein-rich material. Light passe...

Methods that regulate pH

By: HWC, Views: 7883

• The blood flow redistributes fluids that have different pH values between body regions. • The regulation of the blood pH is important to maintain homeostasis. • Blood pH is regulated by: • Chemical buffers. • The respiratory system. • The urinary system. • All thes...

Coaductile pathway, Timing of contraction signal & Conduction system and ECG

By: HWC, Views: 7926

• When the system is healthy, the signal to contract the entire conduction system originates in the SA node - known as the heart's pacemaker. • The SA node triggers contraction because it depolarizes at a faster rate than other parts of the conduction system. • The wave of excitation fr...

Structures that affect circulation - arterioles and vasomotor responses and venous return

By: HWC, Views: 7791

■ Small arteries and arterioles determine SVR. • Blood pressure drops significantly as blood passes through arterioles. • Decreasing arteriole radius and decreased wall elasticity are the main reasons for increased SVR. ■ Small changes in arteriole radius can cause large changes in ...

Hormonal regulation of blood pressure - RAA system

By: HWC, Views: 8157

■ Long-term regulation of MABP is under hormonal control. • Hormones that affect blood pressure and volume: the renin-angiotensin-aldosterone (RAA) system, antidiuretic hormone (ADM), and atrial natriuretic peptide (ANP). ■ Most important hormonal regulator of MABP. Activated by drop in...

Components of the Nervous System

By: Administrator, Views: 433

The nervous system is the part of an animal that coordinates its actions by transmitting signals to and from different parts of its body. The nervous system detects environmental changes that impact the body, then works in tandem with the endocrine system to respond to such events. Nervous tissue...

Mendel's pea plant, Pisum sativum experimental

By: HWC, Views: 5590

Mendel chose the garden pea plant, Pisum sativum, for experimental tests of his ideas about inheritance. Under normal circumstances, the garden pea plant is self-fertilizing. This cross-section shows the gamete-forming structures. Sperm-producing pollen grains form in the stamens. Eggs deve...

Depolarization of the SA node, Action potentials of the myocardium & ANS effects

By: HWC, Views: 7626

• A typical contractile cell in the myocardium has a resting membrane potential. • The resting membrane potential of cells in the SA node is not fixed, and is known as the pacemaker potential. • The action potential of a healthy SA nodal cell has three parts: • Pacemaker potential: ...

Ventilation - phases and driving forces

By: HWC, Views: 7792

Respiration is the exchange of gases between the atmosphere, blood, and cells The combination of 3 processes is required for respiration to occur Ventilation (breathing) External (pulmonary) respiration Internal (tissue) respiration The cardiovascular system assists the respiratory system b...