CONTROL OF THE INTERNAL ENVIRONMENT

1. CONTROL OF THE INTERNAL ENVIRONMENT

2. CONTROL OF THE INTERNAL ENVIRONMENT • THREE MAJOR AREAS OF CONTROL • HEAT • WATER • WASTE (METABOLIC)

3. CONTROL OF THE INTERNAL ENVIRONMENT • HEAT IS GAINED OR LOST IN FOUR WAYS • CONDUCTION • DIRECT TRANSFER OF THERMAL MOTION (HEAT) BETWEEN MOLECULES • CONVECTION • TRANSFER OF HEAT BY THE MOVEMENT OF AIR OR LIQUID PAST A BODY SURFACE • RADIATION • THE EMISSION OF ELECTROMAGNETIC ENERGY • EVAPORATIVE COOLING • THE LOSS OF HEAT FROM THE SURFACE OF A LIQUID THAT IS TRANSFORMING INTO A GAS

4. CONTROL OF THE INTERNAL ENVIRONMENT • THERMOREGULATION • THE MAINTENANCE OF INTERNAL TEMPERATURE WITHIN NARROW LIMITS • DEPENDS ON BOTH HEAT PRODUCTION AND HEAT GAIN OR LOSS • AS EXTENERAL TEMPERATURE FLUCTUATES, A FAIRLY CONSTANT INTERNAL TEMPERATURE IS MAINTAINED BY: • ALTERING THE RATE OF METABOLIC HEAT PRODUCTION • MAY CHANGE HEAT GAIN/LOSS BY CONDUCTION, CONVECTION, RADIATION, OR EVAPORATIVE COOLING

5. CONTROL OF THE INTERNAL ENVIRONMENT • THERMOREGULATION • DEPENDS ON BOTH HEAT PRODUCTION AND HEAT GAIN OR LOSS • CHANGING BLOOD FLOW AT SKIN ALSO IMPACTS HEAT GAIN/LOSS • COUNTERCURRENT HEAT EXCHANGE • SMALL ARTERIES CARRYING COOL BLOOD INWARD ARE PARALLELED BY SMALL VEINS CARRYING WARM BLOOD OUTWARD FROM THE INNER BODY

6. CONTROL OF THE INTERNAL ENVIRONMENT • COUNTERCURRENT HEAT EXCHANGE

7. CONTROL OF THE INTERNAL ENVIRONMENT • BEHAVIOR OFTEN AFFECTS BODY TEMPERATURE • RELOCATING HABITATS • BATHING • CLOTHING IS UNIQUE BEHAVIOR TO HUMANS

8. CONTROL OF THE INTERNAL ENVIRONMENT • REDUCING THE METABOLIC RATE SAVES ENERGY • TORPOR • A STATE OF REDUCED ACTIVITY IN WHICH BODY TEMPERATURE AND METABOLIC RATE DECREASE AND THE HEART AND RESPIRATORY SYSTEM SLOW DOWN • HIBERNATION • A LONG TERM TORPOR; LIVE OFF OF STORED BODY FAT • ESTIVATION • A TYPE OF SUMMER TORPOR

9. CONTROL OF THE INTERNAL ENVIRONMENT • OSMOREGULATION • CONTROLLING THE GAIN AND LOSS OF WATER AND DISSOLVED SOLUTES • OSMOCONFORMERS • BODY FLUIDS HAVE THESAME SOLUTECONCENTRATION AS THESEAWATER; NO NET GAIN ORLOSS OF WATER • OSMOREGULATORS • USE ENERGY TO CONTROL WATER LOSS OR GAIN

10. CONTROL OF THE INTERNAL ENVIRONMENT • OSMOREGULATORS • LAND ANIMALS MAIN PROBLEM IS LIMITING WATER LOSS (DEHYDRATION) • URINE • WASTE PRODUCT OFTHE EXCRETORYSYSTEM • SWEATING • 99% WATER • 2 % WATER LOSS CANDECREASE AEROBICACTIVITY BY 10 %5 % LOSS CAN LEAD TOSERIOUS HEALTH RISKS

11. CONTROL OF THE INTERNAL ENVIRONMENT • ANIMALS MUST DISPOSE OF NITROGENOUS WASTES (METABOLIC WASTES) • AMMONIA • MOST TOXIC; ONLY FOUNDIN AQUATIC ORGANISMS • UREA • 100,000x LESS TOXIC THANAMMONIA • URIC ACID • LARGELY INSOLUBLE IN WATER;NON-TOXIC

12. CONTROL OF THE INTERNAL ENVIRONMENT • EXCRETORY SYSTEMS

13. CONTROL OF THE INTERNAL ENVIRONMENT • THE EXCRETORY SYSTEM • KIDNEY • MAJOR ORGANOF THE HUMANEXCRETORY SYSTEM • URETER • DUCT THATCONNECTS THEKIDNEY TO BLADDER • URINARY BLADDER • STORAGE SAC FORURINE • URETHRA • TUBE THAT LEADS FROMBLADDER OUT THE BODY

14. CONTROL OF THE INTERNAL ENVIRONMENT • KIDNEY • FILTERS THE BLOOD;REFINES THE URINE • 2 MAIN REGIONS • RENAL CORTEX • RENAL MEDULLA • NEPHRONS • FUNCTIONALUNIT OF THEKIDNEY

15. CONTROL OF THE INTERNAL ENVIRONMENT • NEPHRONS – FUCNTIONAL UNIT OF KIDNEY

16. CONTROL OF THE INTERNAL ENVIRONMENT • NEPHRONS – FUCNTIONAL UNIT OF KIDNEY • GLOMERULUS • BALL OF CAPILLARIES ENVELOPED BY BOWMAN’SCAPSULE • BOWMAN’S CAPSULE • RECEIVING END OF KIDNEY • COLLECTING DUCT • CARRIES URINE TO RENALPELVIS • PROXIMAL TUBULE – REFINES FILTRATE • **LOOP OF HENLE– REFINES FILTRATE** • DISTAL TUBULE – REFOMES FILTRATE

17. CONTROL OF THE INTERNAL ENVIRONMENT • OVERVIEW: THE KEY FUNCTIONS OF THE EXCRETORY SYSTEM ARE FILTRATION, REABSORPTION, SECRETION, AND EXCRETION

18. CONTROL OF THE INTERNAL ENVIRONMENT • OVERVIEW: THE KEY FUNCTIONS OF THE EXCRETORY SYSTEM ARE FILTRATION, REABSORPTION, SECRETION, AND EXCRETION • FILTRATION • WATER AND VIRTUALLY ALL OTHER MOLECULES SMALL ENOUGH TO BE FORCED THROUGH THE CAPILLARY WALL ENTER THE NEPRHON TUBULE FROM THE GLOMERULUS • REABSORPTION • WATER AND VALUABLE SOLUTES, INCLUDING GLUCOSE, SALTS, AND AMINO ACIDS, ARE RECLAIMED FROM THE FILTRATE AND RETURNED TO THE BLOOD • SECRETION • CERTAIN SUBSTANCES ARE REMOVED FROM THE BLOOD AND ADDED TO THE FILTRATE • EXCRETION • URINE PASSES FROM THE KIDNEYS TO THE OUTSIDE VIA THE URETERS, URINARY BLADDER, AND URETHRA

19. CONTROL OF THE INTERNAL ENVIRONMENT • FROM BLOOD FILTRATE TO URINE: A CLOSER LOOK

20. CONTROL OF THE INTERNAL ENVIRONMENT • FROM BLOOD FILTRATE TO URINE: A CLOSER LOOK • DISTAL AND PROXIMALTUBULES FOCUS ONNUTRIENT REABSORPTION • LOOP OF HENLE ANDCOLLECTING DUCT FOCUSON WATER REABSORPTION

21. CONTROL OF THE INTERNAL ENVIRONMENT • KIDNEY FAILURE CAN KILL!! • CAUSES OF KIDNEY FAILURE • HYPERTENSION; DIABETES; ALCOHOL, DRUG USE • KIDNEY DIALYSIS CAN BE A LIFESAVER • DIALYSIS • SEPARATION; ARTIFICIAL KIDNEY • KIDNEYSTONES ANDGOUT AREALSO SERIOUSCONDITIONS

22. CONTROL OF THE INTERNAL ENVIRONMENT • THE LIVER IS A VITAL ORGAN FOR HOMEOSTASIS • SYNTHESIZES UREA FROM AMMONIA • DETOXIFIES MANY COMPOUNDS • HEPATIC PORTAL VESSEL • CONVEYS BLOOD DIRECTLY TO LIVER • MAY BRANCH OF STOMACH OR INTESTINE • GIVES LIVER A CHANCE TO DETOXIFY ALL BLOOD BEFORE IT REACHES HEART • INVOLVED IN BLOOD-SUGAR MAINTENANCE • CONVERTS EXCESS GLUCOSE TO GLYCOGEN

23. CONTROL OF THE INTERNAL ENVIRONMENT • ANOTHER IMPORTANT ASPECT OF HOMEOSTASIS IS KEEPING INTERNAL BALANCE AT ANOTHER LEVEL…FOR INSTANCE, HOW DO YOU CONTROL BLOOD-SUGAR LEVELS?? • THROUGH THE HELP OF THE ENDOCRINE SYSTEM!!!