Warm-Up 3/28

1. Stimulus is a cause of physical response:something that causes a physical response in an organism, e.g. a drug or an electrical impulse
2. Medulla oblongata is a portion of the hindbrain that controls autonomic functionssuch as breathing, digestion and heart rate. Hypothalamus is a part of the brain does the job of connecting the endocrine system with the nervous system through the pituitary gland.
3.  Mechanoreceptors are receptor cells that detect sound 
4. 
5. Processing visual stimuli: Edge enhancement is a ‘pre- central nervous system ‘processing of information on the retina itself. This processing is not carried out by part of the brain but by the organisation of the retinal cells.

Contralateral processing is the way in which the brain collects and integrates information from the eyes to create the perception of seeing. Both these processes require a more detailed knowledge of the retina and brain. It should also be noted that this biology is still the subject of much research and the ideas presented are hypothetical.

Warm-Up 3/2

1. Steps in oogenesis:

Oogenesis is the process by which oogonia (primitive female egg cell developed during fetal development) becomes a zygote (the result of the mating of sperm and egg). During the first phase, the oogonia start meiosis but are stopped at prophase meiosis I during fetal development. During the second phase, increasing levels of FSH (follicle stimulating hormone) during puberty cause the primary follicular cells to grow and start producing estrogen. In the third phase, the secondary oocyte begins meiosis II and stops in metaphase. A secondary oocyte is ovulated. If the oocyte is fertilized, meisosis II resumes. The oocyte splits into an ovum and a second polar body. The sperm and ovum unite and form a diploid zygote.

2. Steps of spermatogenesis:

Spermatogenesis is the process whereby the seminiferous tubules produce sperm. There are three steps in spermatogenesis: 1) meiosis, during which the number of chromosomes in the cell is reduced to half or 23 chromosomes each; 2) meiosis II, during which each haploid cell forms spermatids; and 3) spermiogenesis, during which each spermatid develops into a sperm cell with a head and tail. The entire process of spermatogenesis takes about 64 days.

3. 

Spermatogenesis	Oogenesis
Number of gametes
Principle: continuous production. Although from puberty to old age sperm cells are constantly being engendered, the production is subject to extreme fluctuations regarding both quantity and quality.	Principle: Using up the oocytes generated before birth. Continual decrease of the oocytes, beginning with the fetal period. Exhaustion of the supply at menopause.
Meiotic output
Four functioning, small (head 4 mm), motile spermatozoids at the end of the meiosis	One large, immotile oocyte (diameter 120 mm) and three shriveled polar bodies are left at the end of the meiosis
Fetal period
No meiotic divisions	Entering into meiosis (arrested in the dictyotene stage)
No germ cell production	Production of the entire supply of germ cells

Warm-Up 2/27

1. fibrin

2. high pressure in afferent arterioles; leads to ultrafiltration in the glomerulus/through fenestrated capillaries in the glomerulus; drains through the Bowman’s capsule to the proximal convoluted tubule;

3. Water and solutes from filtrate within the nephron. The lining of the PCT contains many protein channels, which use both active and passive transport to move substances such as glucose and electrolytes across the tubule's lining and into the interstitial fluid for reabsorption

4. Benefits of vaccination

• Some diseases, such as small pox, can be eradicated.
• Deaths can be prevented, ex. from measles.
• Long-term disabilities can be prevented

• Rubella in pregnant women can lead to birth defects
• Mumps can cause infertility in men.

• Dangers of vaccination

• Immunity developed after vaccination may not be as effective as immunity developed in response to the actual disease.
• Dangers of side effects of some vaccines include:

• Whooping cough, vaccine can cause brain damage.
• Pregnant women, cancer patients, and others can be harmed by cross-infection from people vaccinated with the live virus, ex. smallpox vaccine.