Download CONTROL OF THE INTERNAL ENVIRONMENT

CONTROL OF THE INTERNAL
ENVIRONMENT
CONTROL OF THE INTERNAL
ENVIRONMENT
• THREE MAJOR AREAS OF CONTROL
– HEAT
– WATER
– WASTE (METABOLIC)
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
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
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
CONTROL OF THE INTERNAL
ENVIRONMENT
• COUNTERCURRENT HEAT EXCHANGE
CONTROL OF THE INTERNAL
ENVIRONMENT
• BEHAVIOR OFTEN AFFECTS BODY
TEMPERATURE
– RELOCATING HABITATS
– BATHING
– CLOTHING IS UNIQUE BEHAVIOR TO HUMANS
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
CONTROL OF THE INTERNAL
ENVIRONMENT
• OSMOREGULATION
– CONTROLLING THE GAIN
AND LOSS OF WATER AND
DISSOLVED SOLUTES
– OSMOCONFORMERS
• BODY FLUIDS HAVE THE
SAME SOLUTE
CONCENTRATION AS THE
SEAWATER; NO NET GAIN OR
LOSS OF WATER
– OSMOREGULATORS
• USE ENERGY TO CONTROL
WATER LOSS OR GAIN
CONTROL OF THE INTERNAL
ENVIRONMENT
• OSMOREGULATORS
– LAND ANIMALS MAIN
PROBLEM IS LIMITING
WATER LOSS
(DEHYDRATION)
• URINE
– WASTE PRODUCT OF
THE EXCRETORY
SYSTEM
• SWEATING
– 99% WATER
– 2 % WATER LOSS CAN
DECREASE AEROBIC
ACTIVITY BY 10 %
5 % LOSS CAN LEAD TO
SERIOUS HEALTH RISKS
CONTROL OF THE INTERNAL
ENVIRONMENT
• ANIMALS MUST DISPOSE
OF NITROGENOUS WASTES
(METABOLIC WASTES)
– AMMONIA
• MOST TOXIC; ONLY FOUND
IN AQUATIC ORGANISMS
– UREA
• 100,000x LESS TOXIC THAN
AMMONIA
– URIC ACID
• LARGELY INSOLUBLE IN WATER;
NON-TOXIC
CONTROL OF THE INTERNAL
ENVIRONMENT
• EXCRETORY SYSTEMS
CONTROL OF THE INTERNAL
ENVIRONMENT
• THE EXCRETORY SYSTEM
– KIDNEY
• MAJOR ORGAN
OF THE HUMAN
EXCRETORY SYSTEM
– URETER
• DUCT THAT
CONNECTS THE
KIDNEY TO BLADDER
– URINARY BLADDER
• STORAGE SAC FOR
URINE
– URETHRA
• TUBE THAT LEADS FROM
BLADDER OUT THE BODY
CONTROL OF THE INTERNAL
ENVIRONMENT
• KIDNEY
– FILTERS THE BLOOD;
REFINES THE URINE
– 2 MAIN REGIONS
• RENAL CORTEX
• RENAL MEDULLA
– NEPHRONS
• FUNCTIONAL
UNIT OF THE
KIDNEY
CONTROL OF THE INTERNAL
ENVIRONMENT
• NEPHRONS – FUCNTIONAL UNIT OF KIDNEY
CONTROL OF THE INTERNAL
ENVIRONMENT
• NEPHRONS – FUCNTIONAL UNIT OF KIDNEY
• GLOMERULUS
– BALL OF CAPILLARIES
ENVELOPED BY BOWMAN’S
CAPSULE
• BOWMAN’S CAPSULE
– RECEIVING END OF KIDNEY
• COLLECTING DUCT
– CARRIES URINE TO RENAL
PELVIS
• PROXIMAL TUBULE – REFINES FILTRATE
• **LOOP OF HENLE – REFINES FILTRATE**
• DISTAL TUBULE – REFOMES FILTRATE
CONTROL OF THE INTERNAL
ENVIRONMENT
• OVERVIEW: THE KEY
FUNCTIONS OF THE
EXCRETORY SYSTEM ARE
FILTRATION, REABSORPTION,
SECRETION, AND EXCRETION
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
CONTROL OF THE INTERNAL
ENVIRONMENT
• FROM BLOOD FILTRATE TO URINE: A CLOSER
LOOK
CONTROL OF THE INTERNAL
ENVIRONMENT
• FROM BLOOD FILTRATE TO URINE: A CLOSER
LOOK
– DISTAL AND PROXIMAL
TUBULES FOCUS ON
NUTRIENT REABSORPTION
– LOOP OF HENLE AND
COLLECTING DUCT FOCUS
ON WATER REABSORPTION
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
• KIDNEY
STONES AND
GOUT ARE
ALSO SERIOUS
CONDITIONS
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
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!!!