The Biological Basis of Behavior - Endocrine System, Genes, and Neurotransmitters.

Endocrine System

a collection of glands that produce hormones

Homoeostasis

process by which living organisms maintain a stable internal environment despite changes in the external environment

Hypothalamus

It secrets hormones known as releasing factors that cause the pituitary gland to release other hormones, including growth hormones

Hormones: Releases releasing and inhibiting hormones that control the pituitary gland.

• Anterior Pituitary

• Posterior Pituitary

What are the two hormones of the Pituitary Gland?

Anterior Pituitary

Produces Growth and Hormone

Posterior Pituitary

Stores and releases Oxytocin (stimulates uterine contractions and milk ejection) and Antidiuretic Hormone (ADH) (regulates water balance).

• Thyroxine (T4) and Triiodothyronine (T3)

• Calcitonin

What are the hormones under Thyroid Gland?

Thyroxine (T4) and Triiodothyronine (T3)

regulate metabolism, growth, and development

Calcitonin

lowers blood calcium levels

Parathyroid Hormone (PTH)

increases blood calcium levels by stimulating bone resorption and
calcium reabsorption in the kidneys

Adrenal Cortes

Produces Cortisol (regulates metabolism and stress response), Aldosterone (regulates sodium and potassium balance), and Androgens (sex hormones).

Adrenal Medulla

Produces Epinephrine and Norepinephrine (fight-or-flight response).

Insulin

lowers blood glucose levels

Glucagon

raises blood glucose levels

Ovaries

Produce Estrogens and Progesterone

• regulate menstrual cycle, pregnancy, and secondary
  sexual characteristics

Testes

Produce Testosterone

• regulates sperm production and secondary sexual characteristics

Melatonin

regulates sleep-wake cycles

• Metabolism

• Growth and Development

• Reproduction

• Stress Response

• Homeostasis

What are the functions of hormones?

Genes

are segments of DNA that contain instructions for building proteins. These proteins influence the development and functioning of various systems in the body, including the brain.

Genetic Makeup

An individual’s genetic makeup (genotype) can affect a range of psychological traits such as intelligence, temperament, and susceptibility to mental health disorders.

Genetics Inheritance

where genes from both parents contribute to an individual's characteristics. For instance, genetic predispositions can influence
behaviors and mental health conditions, such as depression or anxiety.

Polygenic Traits

they are influenced by multiple genes. This makes it challenging to pinpoint a single gene responsible for a trait. Examples include complex traits like intelligence and personality

Gene-Environment Interaction

Behavior results from the interaction between genetic predispositions and environmental influences. For example, a person may have a genetic predisposition to anxiety, but environmental factors such as stressful life events or parenting styles can influence whether or not this predisposition leads to an anxiety disorder.

Gene-Environment Correlation

This concept refers to how individuals with certain genetic traits may seek out or create environments that reinforce those traits. For instance, a person genetically predisposed to be outgoing may seek social situations more often, which can enhance their social skills.

Epigenetic Changes

Environmental factors can influence gene expression without altering the DNA sequence. These changes can affect how genes are turned on or off and can have long-lasting effects on behavior.

Innate Temperament

includes traits like emotional reactivity and self-regulation, has a
genetic component. For instance, some children are naturally more
resilient or more sensitive to stress, and these tendencies are partly
inherited.

Heritability of Intelligence

genetic factors contribute to this range of variance in IQ scores among individuals.

Genetic Risk

Twin and family studies indicate that these disorders can run in families, suggesting a hereditary risk.

Genetic Predisposition

an increased likelihood or susceptibility of developing a particular disease or trait, stemming from specific inherited genetic variations

Twin studies compare identical
(monozygotic) twins, who share 100% of their genes, with fraternal
(dizygotic) twins, who share about 50% of their genes.

Identical vs. Fraternal Twins

Identifying Specific Genes

This involves examining genetic variations (alleles) and their
associations with behaviors.

Personal Traits and Potential

Understanding the genetic basis of behavior can provide insights into individual differences and potential. For instance, recognizing a genetic predisposition to certain skills or traits can help individuals make more informed life choices.

Privacy and Discrimination

Knowledge of genetic influences on behavior raises ethical concerns about privacy and potential discrimination.

Tailoring Interventions

Genetic information can inform personalized approaches to psychological interventions and treatments, potentially
leading to more effective strategies for managing mental health
conditions.05

Neurotransmitters

are molecules released by neurons (nerve cells) that travel across the synaptic cleft (the space between neurons) to transmit signals to other neurons or target cells. This communication helps regulate
various physiological and psychological processes.

Acetylcholine (ACH)

Involved in muscle contraction, attention, and memory

• Antidepressants

• Antipsychotics

What are the medication and therapy of Neurotransmitters and Behavior

Endorphins

Act as natural painkillers and mood enhancers.

Glutamate

Main excitatory neurotransmitter involved in learning and memory.

Gaba (Gamma-aminobutyric Acid

Main inhibitory neurotransmitter that reduces neuronal excitability

Norepinephrine

Involved in arousal, alertness, and stress response.

Serotonin

Regulates mood, sleep, appetite, and pain

Dopamine

Regulates pleasure, reward, motor control, and motivation

Environmental vs. Genetic Influence

Adoption studies compare adopted children with their biological and adoptive parents. These studies help disentangle the effects of genetics from those of the environment.