Viktor Hamburger was a graduate student in Spemann’s department at Freiburg during the years that the organizer graft experiments were being performed. Below is the transcript from his Nobel Lecture 1935. Spemann received the 1935 Nobel Prize in Physiology or Medicine 'for his discovery of the organizer effect in embryonic development'. The same region in birds it is known as 'Hensen's node' named for Victor Hensen (1835 – 1924) and is also known generally as the primitive node or knot. This region was also called the 'Spemann's organiser'. The parasympathetic nervous system promotes responses that are the opposite of the sympathetic nervous system, such as digestion and maintenance.Hans Spemann (1869 - 1941) was a German embryologist who worked extensively on amphibian development and was the discoverer of the organiser region (or primitive node) the controller of gastrulation (1924). The central nervous system typically produces reflex arcs and processes external stimuli. The Enteric peripheral nervous system controls the digestive glands. In the presence of stress, the heart beats faster and stronger, more blood is carried to the vital organs, and the pupils dilate to prepare the body to defend itself. The Sympathetic Nervous System activates the body s fight-or-flight response. Which of the following nervous system directs the skeletal muscles to respond in the body's fight-or-flight response? Embryogenesis is completed by the fetus stage. During the blastula stage, the inner cell pmass and blastopore are formed. In which of the following stages of embroylogical development are the main germ layers (ectoderm, endoderm, and mesoderm) formed?ĭuring the gastrula stage, the germ layers are formed. Which of the following structures is an irregularly shaped bone? Which of the following structures stores urine before excretion? This is a single replacement reaction because element B is replaced by element C. Which of the following formulas best summarizes a simple replacement reaction?

Which of the following best describes matter in which the components cannot be broken down into simpler substances?Īn element is a substance made of a single type of atoms that are generally held together by physical forces.

The normal dihybrid ratio is 9:3:3:1, so this isi a modified dihybrid ratio. Which of the following best describes the ratio? Which of the following produces ammonia by deamination in the liver?Ī cross between two heterozygous F1 plants produces a ratio of 15:1 in the F2 offspring. Which of the following anti-body-secreting cells is triggered to proliferate upon vaccination? Which of the following is the region of the kidney that contains the glomerulus of the nephron? Which of the following is the tube that carries both sperm and urine for release outside the body? Oxygen/carbon dioxide exchange (Lungs, trachea, larynx, nasal cavities, and pharynx)īreakdown of which of the following begins.

Blastopore