Week Seven: “Only the Good Die Young”

Read pp. 97-101: Senescence

Read Chapter 10: Lungs

Read Chapter 11 (283-293) Kidneys

Announcements for February 22^nd, 2001

1. Study sheet #4 and “senescence” workshop handed out today and due Thursday the 1^st of March

2. Upper division students turn back graded material to me NOW

3. Final exam questions handed out on March 1^st and in-class writing on March 8^th

4. Deadline for “Teach for America” is February 26^th

5. Any other announcements

Objectives:

· To understand how and why certain organs stop working effectively during aging

· To understand what the lungs do and how they function

· To understand what the kidneys do and how they function

Important concepts

1. Organs become less effective at doing their job over time

2. You need your organs to work in concert in order to stay alive

3. Lungs are responsible for gas exchange with the environment (O2 in, CO2 out)

4. Kidneys are responsible for filtering your blood

AGING AND SENESCENCE

1. Aging involves slow changes in the structure and function of the body

· Senescence involves a reduced capacity of the body to defend itself, repair itself and maintain a constant internal environment

· Death is marked by the complete inability of the body to regulate and maintain itself.

2. Theories to explain aging and senescence

· genetic mutations

· accumulation of free radicals

· accumulation of waste products

· development of auto-immunity

· ticking of the biological clock

· cross-linkage of proteins

· telomere breakdown

LUNGS

1. The function of the respiratory system can be divided into 3 parts

· breathing is the movement of air in and out of the lungs

· external respiration is the exchange of gases between lung and blood

· internal respiration is the exchange of gases between cells and blood

Q: what gases need to be exchanged?

2. Breathing is a passive physical event caused by the downward movement of your diaphragm

Q: what muscles are involved in breathing?

Q: do you consciously control your breathing?

3. Air passes through the following structures on its way to the bloodstream

· nasal and mouth cavity Fig. 10.1

· pharynx (common throat) and trachea

· bronchus

· bronchioles

· alveoli

4. The lung is comprised of the Fig. 10.7

· bronchi, bronchioles, alveoli and associated tissues

· pleural membrane lines the lungs and secretes fluid

Q: what is the function of the pleural fluid?

5. Respiratory problems include Fig. 10.18

· pneumonia

· emphysema

· lung cancer

· tuberculosis

· asthma

6. Gas exchange takes place in the alveoli Fig. 10.8

· alveoli are thin membraned and well vascularized

7. Gases are transported to the tissues via the circulatory system Fig. 10.13

· CO2 is transported as CO2 or HCO3- (bicarbonate)

· O2 is mostly transported on hemoglobin

Q: why does O2 diffuse from the alveoli into the blood?

KINDEYS

1. The main function of the kidneys is to filter blood

· kidneys also regulate blood flow and water levels

Q: Why do you want your blood filtered?

2. From the kidneys the filtrated passes through the Fig. 11.2

· ureter which transports urine to the bladder

· urinary bladder which stores urine

· urethra which carries urine to the outside

3. Structure of the kidney is complex Fig. 11.6

4. Three main processed happen in the kidney Fig. 11.8

· filtration of blood to form potential urine

· reabsorption of urine components back into bloodstream

· secretion of blood components into urine

Q: why do you want to reabsorb stuff back into bloodstream?

Q: what types of molecules are secreted into urine?

5. Kidney problems

· kidney stones

· glomerulo-nephritis

· urinary tract infection

· hemodialysis for chronic kidney failure

· diabetes insipidus

· diabetes mellitus is a hormonal problem, not at kidney problem

Q: what is the commonality between the two types of diabetes?