Lecture 10 (homoeostasis and behavior) Flashcards
How are the homeostatic functions regulated?
By negative feedback.
What does it mean that humans are endotherms?
They produce and regulate their own temperature.
Which part of the brain monitors and controls body temperature?
Hypothalamus.
Where do hypothalamus send its signals about body temperature to?
Hypothalamus receive input and sends signal through the brain stem which ends up in the spinal cord.
What is osmosis?
Passive movements of water molecules over a semipermeable membrane until a uniform concentration is achieved.
What happens in osmosis?
If there is put more salt on one side than on the other, the water from the less salty water will come over to the side with more salty water to balance of the concentration of water and salt.
Which part of the brain monitors nutrient and energy levels?
Hypothalamus. The nervous system controls appetite and digestion.
How much of our energy intake is spent on basal metabolism?
55 % of the food we eat.
What are carbohydrates broken down to?
Glucose and glucogen.
Which part of the brain is glucose especially important for?
The brain because it is the only energy source it can use.
Where can glucogen be stored for later use?
In the liver and muscles.
Glucogenesis is the process of?
Where glucose is converted into glucogen. Regulated by insulin.
Glycogenolysis is the process of?
Conversion of glucogen back into glucose. Mediated by glucagon.
What is the problem with temporary diets?
Diets can reduce your basal metabolism because your body can’t really understand that you suddenly eat less than normal. This can lead them to later have a harder time losing weight again. Basal metabolism will keep on getting reduced.
What is the microbime?
Microorganisms of the gut.
What does the microbime depend on?
Diet, current and previous infections, antibiotics.
In which systems does microbime play a big role?
In endocrine and neuronal signaling.
Relation between the microbime and depression?
People with depression show altered microbiome composition – these abnormalities persist during remission.
What is sexual differentiation?
The process by which individuals develop either male or female bodies and behaviors. In mammals this process begins before birth and continues into adulthood.
Chromosomes of women and men?
XX (women), XY (men)
Which protein is responsible for the development of testes?
SRY. Not produced in XX individuals.
What will happen if the body is and isn’t exposed to testicular hormones?
If the body is exposed to testicular hormones, it will begin to for masculine characteristics. If non-exposure, it will begin to develop feminine characteristics.
Where do women tend to be superior?
Superior abilities in fine motor skills, verbal fluency and empathy.
Where do men tend to be superior?
Superior abilities in spatial tasks and assertiveness.
Lesions of the hypothalamus can interfere with what rhythm?
The circadian. More precisely in the suprachiasmatic nucleus.
How is the circadian clock regulated by external clues?
The light hits the eye where cones and rods provide form vision. This send it further to the entrainment pathway. This consists of specialized retinal ganglion cells containing melanopsin that project to the SCN via the retinohypothalamic tract. This will end with consistent rhythm of being active and inactive.
Which hormone regulates the circadian clock?
Melatonin. High at night, low in the day.
REM-sleep?
Rapid eye movement sleep.
In many ways is it similar to the pattern of an awake individual, but the skeletal muscles are completely relaxed and limp. Deeply relaxed muscles. Intense brain activity. Brainstem regions are profoundly inhibiting motor neurons. Breathing and pulse rates become irregular.
Non-REM sleep stage 1
slowing of heart rate and a reduction of muscle tension. The eyes roll about slowly under the closed eyelids. Lasts several minutes.
Non-REM sleep stage 2
if awakened during this stage or stage 1, many people will deny sleeping.
Non-REM sleep stage 3
very slow waves. A widespread synchronization of cortical activity.
When do we experience vivid dreams?
REM-sleep.
Which stage of the sleep schedule do elderly people spend less time in?
Stage 3.
Which stage of the sleep schedule do dementia people spend less time in?
Stage 3.
What can prolonged total sleep deprivation lead to?
Compromised immune system and death.
If the brainstem is electrical stimulated, what will happen?
This promotes wakefulness and alertness.
What do the forebrain system do in sleep?
It can by itself display slow-wave-sleep (stage 3)
Which system of the brain triggers REM sleep?
Pons.
What do hypothalamus have to do with sleep?
It affects the brainstem, forebrain and pons to determine whether the brain will be awake or asleep.
What do sleep conserve?
Energy.
The link between sleep and cancer?
It is found that people who work at night and sleep in the daytime are more likely to develop cancer.
Sleep and diabetes?
People who sleep less than 5 hours a night are more likely to develop diabetes.
What do the glia control while we sleep?
Glia control the flow of cerebrospinal fluid through a microscopic network of channels throughout the brain, collecting and disposing of toxins that build up.
Parthenogenesis?
reproduction without sex.
Which hormones affect the brain to activate mating behavior?
Steroid hormones.
What happens after lesions to the medial amygdala?
abolishment of the penile erection.
The difference in hormone secretion in both sexes?
Developing testes produce several hormones, fetal ovaries produce very little hormone.
What happens if a person only has one chromosome, a single X?
Turner’s syndrome.
Congenital adrenal hyperplasia (CAH)?
a XX individual (female) but with an intersex appearance.
Androgen insensitivity syndrome (AIS)?
the gene for the androgen receptor is found on the X chromosome. It is a masculine sexual differentiation but genitals are female or between female and male.
Organizational effect?
The same testicular steroids that masculinize the genitalia during early development also masculinize the developing brain.
The organizational hypothesis?
a single steroid signal (androgen) diffuses through all tissues, masculinizing the body, the brain, and behavior.
The aromatization hypothesis?
during normal rodent development, testicular androgens enter the brain and are there converted into estrogens, and these estrogens are what act on neurons to masculinize the developing rodent nervous system
Osmotic thirst?
a high extracellular concentration of solute will lead to thirst.
Happens in processes as respiration, perspiration, and urination.
Hypovolemic thirst?
a low extracellular volume due to the loss of body fluids will lead to thirst.
Leptin (peptide)?
fat cells produce leptin and then secrete the protein into the bloodstream.
What does the body monitor in circulating leptin?
The brain seems to monitor circulating leptin levels to measure and regulate the body’s energy reserves in the form of fat.
Ghrelin?
a powerful appetite stimulant released into the bloodstream by endocrine cells of the stomach. The levels rise when fasting and drop right after eating a meal.
PYY3-36?
low level in the blood prior to eating but rises rapidly on ingestion of a meal. May act opposite ghrelin.
Diurnal?
Active during the day
Nocturnal?
Active during dark periods.
Infradian?
a rhythm longer than 24 hours
Biological functions of sleep?
- Sleep conserves energy
- Sleep enforces niche adaption
- Sleep restores the body and brain
- Sleep aids memory consolidation
Somnambulism?
Sleepwalking.
When does somnambulism take place?
happens during stage 3 SWS. Therefore, they’re more common in the first half of the night.
REM behavior disorder (RBD)?
characterized by organized behavior in a person who appears to be asleep. Like screamning and stuff while asleep.
