PSYC 3121 - Chapter 2: Systems of the body

Nervous system

A complex network pf nerve fibres that functions to regulate important bodily functions

Two main types of nerves in the nervous system

Sensory nerve fibres

Motor nerve fibres

Sensory nerve fibres

Provide information to the brain and spinal cord via sensory receptors

Motor nerve fibres

Provide information/output from the brain or spinal cord to muscles and organs

Central Nervous System (CNS)

Made up of brain and spinal cord. Carries voluntary nerve impulses to skeletal muscles and skin and carries involuntary impulses to muscles and glands

Peripheral Nervous System (PNS)

All the nerves in the body including those connected to the brain and spinal cord. Consists of Somatic nervous system and Autonomic nervous system.

Somatic Nervous System

Connects the nerve fibres to voluntary muscles. Controls voluntary movements and provides sensory information back to the brain about that voluntary movement.

Autonomic Nervous System (ANS)

Connects the brain and spinal cord to internal organs, controls involuntary movement. Consists of sympathetic and parasympathetic NS's

Sympathetic Nervous System (SNS)

Plays critical role in preparing the body for stress. Controls the fight or flight system. Referred to as a catabolic system

Catabolic system

Deals with mobilizing and exerting energy

Characteristics of sympathetic ns response

HR and BP increase

Blood diverted to muscles

Respiration increases

Digestion and urination decrease

Pupils dilate

Sweat glands stimulated

Parasympathetic Nervous System (PNS)

Controls activity of organs when not in a stressful situation. Helps to restore the body back to normal state when a stressor has passed. ANS at rest. Referred to as an anabolic system.

Anabolic System

Concerned with conserving energy in our bodies and keeping things normal

The brain takes in information from the peripheral nerves, called _______ or ________ impulses, and interprets it

Sensory, afferent

Afferent/Sensory impulses

Information from the rest of the body that travels to the brain

The brain sends back _____ or ________ impulses to internal organs as well as the extremities of the body so that they can carry out necessary behaviours/movements

Motor, efferent

Efferent/motor impulses

Carry impulses from brain and spinal cord to organs that produce response such as glands and muscles. Away from CNS.

Two types of nerve impulses map onto

Sensory and motor nerves

3 main parts of brain

Hindbrain, midbrain, forebrain

Hindbrain (rhombencephalon)

Medulla, pons, cerebellum

Midbrain (mesencephalon)

Major pathway between the hindbrain and forebrain for sensory and motor impulses. Responsible for auditory an visual reflexes.

Forebrain (prosencephalon)

Composed of the diencephalon and telencephalon

Diencephalon

Thalamus and hypothalamus

Thalamus

Recognizes sensory stimulation from the environment and relays sensory impulses to the cerebral cortex - isn't involved in sense of smell

Hypothalamus

Regulates centers in the medulla, water balance, hunger and sexual appetites. Transition center between the thoughts created by the cerebral cortex and how our thoughts affect our organs.

Telencephalon/Cerebral cortex (cerebrum)

Largest portion of brain, includes left and right hemispheres. Involved in more complex functions - higher order processing, memory, and personality. 4 lobes.

Frontal lobe

Memory storage, motor cortex (ex: movement)

Parietal lobe

Registers and interprets touch, pain, pressure, temperature

Temporal lobe

Processes auditory and olfactory information

Occipital lobe

Processes visual information

Limbic system borders the

Midline of the brain

Limbic system

neural system (including the hippocampus, amygdala, cingulate gyrus, septum and hypothalamus) located below the cerebral hemispheres; associated with emotions and drives.

Parts of thalamus and hypothalamus are included in

Limbic system. Related to socially relevant behaviours.

SNS activation leads to release of two neurotransmitters

Epinephrine and norepinephrine (AKA adrenaline and noradrenaline)

Together, epinephrine and norepinephrine are called the

Catecholamines

The release of catecholamines leads to the changes associated with the

Fight or flight response

Although there are major differences between the different nervous system disorders, they do tend to share some common symptoms — things like:

Impaired cognition,

Issues with mobility,

Bladder issues,

Pain and discomfort, and

just poor overall health.

Epilepsy

Disease of the CNS where the main symptom is seizures. Idiopathic disorder that can be treated with medications and stress management techniques.

Idiopathic disorder

No specific cause has been identified, but there are lots of different things that are thought to contribute to the disorder, including head injury, certain infections, genetics, or problems with nutrition.

Cerebral Palsy

Brain damage caused by lack of O2 supply during child birth, physical trauma. Can also involve seizures, problems hearing, seeing or other senses or mental handicap.

Multiple Sclerosis

The degeneration of certain brain tissues resulting in paralysis. Autoimmune disorder in which the body attacks the myelin sheath surrounding nerves.

Parkinson's Disease

Degeneration of basil ganglia (controls smooth motor coordination). Symptoms include tremors, slow movement, and rigidity. Thought to be related to a lack of the neurotransmitter dopamine.

Huntington's Disease

Hereditary disorder involving chronic mental and physical deterioration and has a very strong genetic basis

Alzheimer's disease

Degenerative disorder of the brain affecting thinking and memory

Endocrine system

System that works closely with the nervous system to make sure our bodies are functioning properly. Responsible for slow-acting responses for a longer duration as oppose to nervous systems fast acting nature. Controlled by hypothalamus and pituitary gland.

Nervous and endocrine systems work closely together and they depend on each other to

Both stimulate and inhibit the activities they are responsible for

The endocrine system is composed of a series of glands that secrete

Hormones in the blood that make a variety of targeted changes to the body

Pituitary gland

Responsible for secreting a variety of hormones, including those that control growth, labour contractions, kidney function, and also controls the secretions of a variety of other glands

Adrenal Glands

Two small glands located on top of the kidneys. Contains adrenal cortex and adrenal medulla.

Adrenal cortex

Releases hormones called steroids - including estrogen and androgens and glucocorticoid's (Ex: cortisol)

Adrenal medulla

Secretes catecholamines (epinephrine and norepinephrine)

Both catecholamines and glucocorticoids play a big role in our response to

Stress

Diabetes

Chronic endocrine disorder in which the body is unable to manufacture or properly use insulin. Type 1 and 2.

Type 1 Diabetes

Pancreas does not produce enough insulin - usually diagnosed in childhood/adolescence. This type is thought to be an autoimmune disorder

Type 2 Diabetes

Body does not properly use insulin - more common, and usually diagnosed later in life. Typically related to lifestyle factors (e.g., diet, stress)

Hypothyroidism

Abnormally low thyroid stimulating hormone (TSH) production. Symptoms include fatigue, weight gain, depression

Hyperthyroidism

Excessive production of TSH. Symptoms include excessive sweating, weight loss, fatigue, tremors

Cardiovascular system

The transport system of the body, which is made up of the heart, blood vessels (arteries, capillaries, and veins), and blood.

Blood transports

Oxygen from lungs to tissues/CO2 from tissues to lungs;

Nutrients throughout our bodies;

Waste from cells to kidneys;

Hormones; and

Heat.

Vessels include

Arteries and veins

Arteries

Carry oxygenated blood from the heart to other organs and tissues. Include capillaries and arterioles.

Capillaries

Smaller vessels that branch off from arteries to individual cells

Arterioles

Tiny branches of the arteries

Veins

Return deoxygenated blood back to the heart

The left side of the heart takes in

Oxygenated blood from the lungs and pumps it into the aorta

Aorta

Main artery leading out of the heart.

After blood exits via aorta to the rest of the body, it comes back into

The right side of the heart, where it is pumped back into the lungs so it can be filled with oxygen again

The heart functions in a series of contractions and relaxations called the cardiac cycle, that has two phases:

Systole and diastole

Systole

Blood pumped out of the heart increasing the BP

Diastole

When the heart relaxes, BP drops, and blood is taking into the heart

Damage to the heart can occur due to

Congenital defects, infection (e.g., salmonella, meningitis), and/or damage over the lifespan (e.g., from lifestyle factors)

Atherosclerosis

Damage caused by plaque build-up (ex: Cholesterol) in the arteries. Main cause of heart disease by reducing blood flow and preventing nutrients from reaching our tissues, which can cause tissue damage.

Damage to artery walls can also cause blood clots. These manifest themselves in two main ways:

Angina pectoris and Myocardial infarction

Angina pectoris

Chest pains due to heart strain resulting from lack of O2 or inadequate removal of waste and CO2

Myocardial infarction

Blood clots blocks the flow of blood to the heart (heart attack)

Arteriosclerosis

Hardening of the arteries, leading to a decrease in elasticity and an increase in blood pressure

Aneurysm

Bulge in a weak part of an artery wall as a result of pressure; when it ruptures, can lead to death from internal bleeding and loss of BP

Phlebitis

Inflammation of a vein wall, resulting in pain, water retention, and greater likelihood of blood clots

Hypertension

Chronically high BP due to high cardiac output or blood flow resistance (peripheral resistance)

Normal BP is

120/80 - above 140/90 is hypertensive

The human body contains ____ L of blood

Five

Just over half of the blood (55%) is made up of

Blood plasma

Blood plasma

The fluid portion of blood, and the rest is made up of blood cells

Our blood cells are made by our

Bone marrow

Types of blood cells

White blood cells

Lymphocytes

Red blood cells

Platelets

White blood cells

Heal the body by absorbing and removing foreign substances. Put simply, they basically eat the foreign invaders and turn them into substances that can be disposed of easily

Lymphocytes

Produce antibodies to fight infection and disease.

Red blood cells

Contain hemoglobin and carry oxygen and CO2 throughout the body

Platelets

Contribute to blood vessel repair and blood clotting

Blood disorders can be related to either the production of

White blood cells or red blood cells

White Cell Production Disorders

Leukemia and Leukopenia

Leukemia

Bone marrow disease and form of cancer causing excessive white cells overloading the blood plasma, reducing red blood cells. The cause is unknown, but links have been discovered to chemicals and smoking

Leukopenia

White cell deficiency, leads to susceptibility to infection and disease. Often appears in conjunction with diseases like tuberculosis, pneumonia, and measles

Red Cell Production Disorders

Anemia, Aplastic anemia and Sickle cell anemia

Anemia

Too few red blood cells or low hemoglobin. Losely related to iron deficiency, because iron is important to the production of hemoglobin.

Aplastic anemia

Problems with the bone marrow in making red blood cells, which results in a lack of oxygen in the blood

Sickle cell anemia

Genetic disorder characterized by an inability to produce normal-shaped blood cells, vulnerable to rupture leaving individual susceptible to anemia.

Clotting disorders include

Hemophilia and Clots/Thromboses

Hemophilia

The body does not produce the substances required to clot the blood. Those with this disorder could bleed to death from a minor injury without medication.

Clots/Thromboses

When vessel walls are damaged due to the buildup of cholesterol, platelets adhere to the walls and build up. Could be fatal when they occur in vessels leading to the heart or brain