Homeostasis

Question 1

All homeostatic control systems have three functional components

Answer 1

start at stimulus
A receptor (or monitor)
A coordinating centre
A regulator (or effector)
end with response

Question 2

The homeostatic control process can be

Answer 2

conscious, such as when you decide to put on a jacket when you feel cold. These are behavioral responses.

unconscious, such as when you start to shiver. These are physiological responses.

Question 3

Negative feedback

Answer 3

Negative feedback systems, (also called negative feedback loops) are mechanisms that make adjustments to bring the systems of the body back to within an acceptable range.
blood pressure

Question 4

ectotherms

Answer 4

Most organisms cannot maintain a constant internal body temperature, regardless of their surroundings

thermostat” for thermoregulation is located in a region of the brain called the hypothalamus

Question 5

when youre hot

Answer 5

heart rate speeds up to pump blood to skin to cool down

sweat

Question 6

when youre cold

Answer 6

vasocontriction limits blood flow and slows heat loss

Question 7

Main organs of the excretory system

Answer 7

kidneys
liver
large Intestine
Your excretory system has three main jobs:

to remove waste
monitor water balance
control pH

Question 8

How does the excretory system help maintain homeostasis?

Answer 8

The excretory system helps maintain homeostasis by filtering out metabolic waste, balancing pH, and monitoring blood pressure.

Question 9

The structure of the kidney

Answer 9

The outer layer is the cortex and encircles the kidney.
The inner layer, called the medulla, is found beneath the cortex.
A hollow chamber, known as the renal pelvis, joins the kidney with the ureter.

Question 10

The functional unit of the kidney

Answer 10

nephrons. They are located in the cortex and extend down into the medulla. Nephrons are surrounded by a mesh of fine blood vessels, called capillaries, that allows waste to diffuse out of the blood.

Each nephron consists of five main parts:

Bowman’s capsule (containing the glomerulus)
Proximal tubule
Loop of Henle
Distal tubule
Collecting duct

DO DIAGRAM ON 5.2

Question 11

blood flow in a nephron

Answer 11

The Bowman’s capsule, the afferent arteriole, and the efferent arteriole (branches into peritubular capillaries are located in the cortex of the kidney.

Blood enters the glomerulus and is filtered, through pressure, into Bowman’s capsule, which is located in the cortex.
The filtrate passes through the proximal tubule, which is also located in the cortex. This is where glucose and amino acids are reabsorbed to the blood.
Next, the filtrate moves down into the loop of Henle, which is located in the medulla of the kidney. Here, water is removed from the filtrate and returned to the blood.
The filtrate then moves through the distal tubule located in the cortex, where hydrogen ions and drugs that are to be excreted in the filtrate are extracted (or secreted) from the blood. Even more water is removed from the filtrate and returned to the blood.
Finally, the filtrate moves into the collecting duct, which is located in the medulla. These ducts collect filtrate (now called urine) from many nephrons and eventually merge in the renal pelvis of the kidney. The urine exits the renal pelvis via the ureter, to be stored in the bladder.

Question 12

Filtration

Answer 12

The movement of fluids from the blood into Bowman’s capsule is called filtration. The dissolved solutes leave the afferent arteriole and enter Bowman’s capsule, which is porous.
Plasma protein, blood cells, and platelets are too large to move through the pores of the glomerulus, while smaller molecules pass through the walls and enter the nephron. It
only uses passive transport.

Question 13

Step 2: Reabsorption

Answer 13

The transfer of essential solutes and water from the nephron back into the blood is called reabsorption. It uses active transport to move sodium (N + ) ions, glucose, and amino
acids back into the blood and it uses passive transport to move water from the nephron back into the blood.

Question 14

Step 3: Secretion

Answer 14

The movement of materials, such as nitrogen-containing waste, excess H + ions, and
some minerals and drugs are secreted into the urine. It only uses passive transport.

Question 15

The roles of the endocrine and nervous systems in water balance

Answer 15

Antidiuretic hormone (ADH), helps to regulate the osmotic pressure of body fluids by causing the kidneys to increase water reabsorption. ADH moves along specialized fibres from the hypothalamus to a gland called the pituitary gland, which stores and releases ADH into the blood.
Changes in osmotic pressure in the blood are picked up by specialized nerve receptors in the hypothalamus called osmoreceptors.

Question 16

Kidneys also play a role in maintaining normal blood pressure.

Answer 16

A hormone called aldosterone acts on the nephrons to increase Na+ reabsorption. Aldosterone is produced in the cortex of the adrenal glands, which lies above the kidneys.
The aldosterone travels in the blood to the kidneys, where it acts on the cells of the distal tubule and collecting duct to increase Na+ transport. When Na+ is reabsorbed, water follows, increasing the blood volume and thus increasing blood pressure.
If low pressure is detected, nearby specialized cells in the adrenal glands, release an enzyme, renin, that converts a plasma protein called angiotensinogen into angiotensin.

Question 17

angiotensinogen into angiotensin.

Answer 17

conversion by renin

It constricts blood vessels, thus increasing blood pressure.
It stimulates the release of aldosterone from the adrenal gland.

Question 18

How does ADH work to control water balance?

Answer 18

The release of ADH by the pituitary gland helps the kidneys to regulate the osmotic concentration of body fluids.
ADH does this by making the upper part of the distal tubule and collecting duct permeable to water.
The water leaves the upper part of the distal tubule and enters the blood, making the urine more concentrated.

Question 19

blood pH is too high

Answer 19

The carbonate ion bonds to any excess H+ ions to form carbonic acid ( H2CO3 ) and so lowers the blood pH.

The carbonic acid breaks down into carbon dioxide and water, and the CO2 is transported to the lungs, where much of it is exhaled.

Question 20

blood pH is too low

Answer 20

The carbonic acid breaks down into H+ ions and water, in order to raise the blood pH.

Question 21

Kidney stones occur

Answer 21

solutes from the blood precipitate (solidify) out of the urine. These solutes can accumulate and lodge themselves in the renal pelvis or move into the narrow ureter. As the kidney stones move into the bladder, they can tear delicate tissue and cause severe pain and discomfort. They can also work their way further down the excretory passage and lodge in the urethra, causing a burning sensation, along with excruciating pain.

Question 22

Diabetes insipidus

Answer 22

ADH-producing cells of the hypothalamus, or the nerve tracts leading from the hypothalamus to the pituitary gland, are destroyed. Without ADH to regulate water reabsorption, urine output increases considerably, so none of the remaining 15% (after the other 85% has been reabsorbed at the proximal tubule), is recovered. As much as 20 L of dilute urine may result, creating a strong thirst response, and a severe need to replace lost water.

Question 23

brights disease

Answer 23

nephritis or the inflammation (swelling) of the nephrons.
Toxins produced by invading microbes destroy the tiny blood vessels, altering the permeability of the nephron. This means that proteins and other large molecules are able to pass into the nephron. When the nephrons are destroyed, no mechanism occurs in the nephron membrane to reabsorb protein; instead, the protein remains in the nephron and draws water from the neighbouring peritubular capillaries, which, in turn, increases the output of urine.

Question 24

The endocrine system is instrumental in:

Answer 24

regulating mood
growth and development
tissue function
metabolism
sexual function
reproductive processes

Question 25

endocrine system

Answer 25

system of glandular tissues that produce and secrete special messenger molecules called hormones, into the blood. hormone” means “to excite or set into motion.”

Question 26

antagonistic hormones

Answer 26

the hormones glucagon and insulin, which are both secreted by the pancreas, have opposite effects in response to high or low blood glucose levels. Hormones that have opposite effects

Question 27

High (hyperglycemia)

Answer 27

After a meal Insulin is released from the beta cells in your pancreas Cells in your muscles, liver, and other organs to become more permeable to glucose. When the glucose is drawn out of your blood, this lowers your blood glucose level. Once in your liver, the glucose is converted to glycogen (the storage form of glucose). symptoms Glucose in the urine. Dehydration and thirst caused by glucose in the nephron, which in turn draws water out of the blood through osmosis. Low energy levels because of a lack of insulin, the permeability of glucose into the cells does not increase, so less glucose is burned and less ATP is made.

Question 28

Low (hypoglycemia)

Answer 28

Long period after last meal Fasting Not enough food ingested Glucagon is released by the alpha cells of the islets of Langerhans. During periods of fasting, glucagon is released and promotes the conversion of glycogen to glucose, which is released into the blood, thus raising the blood sugar level.

Question 29

Type 1 (previously called juvenile onset)

Answer 29

Inability to produce insulin, due to an early degeneration of the beta cells in the islets of Langerhans. Occurs in early childhood Insulin must be taken daily in order to survive

Question 30

Type 2 (Adult onset)

Answer 30

most common Decrease in insulin production or ineffective use of the insulin that the body does produces\ Can be controlled with diet, exercise, and a variety of medications that are used to enhance insulin levels or reduce the level of glucose in the blood

Question 31

Epinephrine Increases

Answer 31

Mobilizes energy release from stored carbohydrates and fats Increases blood glucose and fatty acids Accelerates heart rate and breathing in short term stress also norepi is released

Question 32

Glucagon Increases

Answer 32

Converts glycogen to glucose | in short term stress

Question 33

Insulin Decreases

Answer 33

Decreases the breakdown of glycogen in the liver | short term stress

Question 34

Long-term exposure to stress can cause health problems

Answer 34

Higher blood sugar- Alters osmotic balance between blood and extracellular fluids; can lead to increased fluid uptake by the blood and increased blood pressure Increases water loss from nephron Increased blood pressure Can rupture blood vessels due to higher pressure Increases blood clotting Increased heart rate Can lead to higher blood pressure Can damage heart muscle

Question 35

Male hormones are called

Answer 35

androgens

Question 36

female reproductive cycle, many follicles develop in a process called

Answer 36

oogenesis

Question 37

gonadotropin-releasing hormone (GnRH).

Answer 37

hypothalamus secretes GnRH activates the pituitary gland to secrete and release follicle-stimulating hormone (FSH) and luteinizing hormone (LH).

Question 38

here are three different kinds of glands that affect metabolism:

Answer 38

Thyroid gland - regulates body metabolism and the rate at which blood glucose is metabolized (hormones: triiodothyronine, thyroxine, and calcitonin) Parathyroid glands - regulate calcium ion levels in the blood (hormone: parathyroid hormone) Anterior pituitary gland - influences the growth of long bones and accelerates protein synthesis (hormone: growth hormone (somatotropin))

Question 39

Hyperthyroidism

Answer 39

Individuals who produce high levels of T4 and T3 have a condition called hyperthyroidism. These people may lose weight and may often feel warm, due to the higher respiratory rates they experience because of increased glucose oxidation.

Question 40

Hypothyroidism

Answer 40

those who gain weight easily due to low levels of T4 and T3 production have hypothyroidism. In this condition, glucose is not consumed at normal rates, and it gets stored in the liver. Once the liver reserves are full, the body converts sugar into fat. People who secrete low levels of T4 and T3 often experience muscle weakness, cold intolerance, and have dry skin and hair.

Question 41

Parathyroid hormone will work to increase the calcium levels using three methods:

Answer 41

Bones: It increases the blood calcium levels by accelerating the breakdown of bones to produce higher calcium levels. Kidneys: causes reabsorb calcium ions from the filtrate to increase levels. Small intestine: causes absorption of calcium ions from undigested food to increase levels.

Question 42

What happens when there is an increase in blood calcium levels?

Answer 42

The thyroid gland produces calcitonin which acts on bone cells to decrease the loss of calcium from bones. Thus, decreasing the levels of calcium in the blood.

Question 43

The nervous system has two main divisions

Answer 43

The Central Nervous System (CNS) | The Peripheral Nervous System (PNS)

Question 44

The CNS

Answer 44

acts as a coordinating centre for incoming and outgoing information. The CNS consists of the brain and spinal cord.

Question 45

The PNS

Answer 45

carries information between the organs of the body and the CNS. The PNS consists of nerves. The PNS is further subdivided into the somatic nervous system and the autonomic nervous system. The somatic nervous system controls the: skeletal muscle bones skin ``` Somatic nerves can be either: sensory nerves (which relay sensory information) motor nerves (which generate muscle responses) ```

Question 46

The autonomic nervous system controls the internal organs of the body.

Answer 46

The sympathetic nervous system which controls, for example, the “fight or flight” reaction The parasympathetic nervous system which controls functions such as sleep and digestion

Question 47

The autonomic nervous system controls the internal organs of the body.

Answer 47

The sympathetic nervous system which controls, for example, the “fight or flight” reaction The parasympathetic nervous system which controls functions such as sleep and digestion

Question 48

Glial cells

Answer 48

Glial cells are non-conducting cells. They provide structural support and perform metabolic functions for the nervous system

Question 49

Neurons

Answer 49

Neurons are the functional units of the nervous system,

Question 50

There are three types of neurons:

Answer 50

Sensory neurons These neurons sense and relay information from the environment to the CNS for processing. They are located in clusters called ganglia. Interneurons These neurons link neurons within the body and are found mostly throughout the brain and spinal cord. They integrate and interpret the sensory information and connect neurons to outgoing motor neurons. Motor neurons (also known as efferent neurons) These neurons send information to the “effectors.” Effectors are muscles, organs, and glands.

Question 51

Dendrites

Answer 51

Dendrites are the parts of a neuron that receive information. This comes either from sensory receptors or from other nerve cells, such as motor neurons. Dendrites conduct nerve impulses toward the cell body.

Question 52

cell body

Answer 52

portion of the neuron that contains the nucleus and the majority of the cytoplasm.

Question 53

axon

Answer 53

The axon is an extension of a neuron. It carries nerve impulses away from the cell body towards other neurons or effectors

Question 54

myelin sheath

Answer 54

Axons are often covered with a white coat of fatty protein insulation for the neurons formed by special glial cells called Schwann cells, sections of myelin sheath are known as the nodes of Ranvier. Nerve impulses jump from node to node,

Question 55

reflex arc

Answer 55

simple neural circuit that runs through the spinal cord. It provides a way for a reflex action to occur.

Question 56

A reflex arc begins when a stimulus, such as a burning your finger

Answer 56

The heat on your finger triggers a sensory receptor in your skin. The sensory receptor sends the stimulus to the spinal cord. Interneurons in the spinal cord receive the information and immediately send a signal to the motor neurons. The motor neurons activate an effector organ (for example, the muscles). The effector organ, in this case a muscle, causes an immediate response such as pulling your hand away, occurs. Stimulus → Sensory neuron → Interneuron → Motor neuron → Response

Question 57

doctor scene where he hits patients knee

Answer 57

The doctor is testing the patient’s reflexes or reflex arc. By tapping the patient’s knee with a small hammer, the doctor is stimulating sensory neurons, which stimulate interneurons, which then stimulate motor neurons.

Question 58

resting potential

Answer 58

At rest, the potential across the axon membrane is around –70 mV. This means that the inside of the axon is more negative than the outside. The voltage difference across the membrane during the resting stage

Question 59

action potential

Answer 59

When the axon becomes stimulated, a rapid change occurs in the electrical potential difference across the membrane, so it now registers +40 mV. This means that the inside of the axon is now more positive than the outside.

Question 60

Depolarization: How an action potential is formed

Answer 60

The gates of the sodium channel open, allowing na to enter the cell. the membrane starts to depolarize (the charge across the membrane lessens). Once the charge on the inside becomes positive, the sodium gates close, stopping the influx of sodium. The gates of the potassium channel close.

Question 61

synaptic transmission

Answer 61

The process by which one nerve cell communicates with another nerve cell is called

Question 62

Acetylcholine

Answer 62

common neurotransmitter found in the end plates of many nerve cells. Acetylcholine acts as an excitatory neurotransmitter on many postsynaptic neurons by opening their sodium ion gates and causing depolarization. cholinesterase, to destroy acetylcholine closing sodium gates

Question 63

repolarization

Answer 63

After depolarization, the charge on the inside of the nerve membrane becomes positive. This causes the sodium gates to close, stopping the influx of sodium. A sodium potassium pump, located in the cell membrane, restores the condition of the resting membrane by transporting sodium ions out of the neuron, while moving potassium ions into the neuron, at a ratio of 3 Na+ to 2 K+ ions. The energy for the pump comes from ATP. The process of restoring the original polarity of the nerve membrane is called repolarization.

Question 64

Synapse structure

Answer 64

The neuron transmitting the impulse is called the presynaptic neuron. The neuron receiving the impulse is called the postsynaptic neuron. At the end of the axon in the presynaptic neuron is a plate where small vesicles containing chemicals called neurotransmitters are released. Neurotransmitters diffuse across the synapse and attach to receptors on the postsynaptic neuron, where they cause depolarization.

Question 65

Frontal lobe

Answer 65

responsible for movement of voluntary muscles (walking/speech) linked to intellectual activities, mood and personality, especially self- control, reasoning, and abstract thought

Question 66

Temporal lobe

Answer 66

responsible for vision and hearing | linked to memory and interpretation of sensory information

Question 67

Parietal lobe

Answer 67

responsible for touch and temperature awareness | linked to emotions and interpretation of speech

Question 68

Occipital lobe

Answer 68

responsible for vision | linked to interpretation of visual information

Question 69

cerebellum

Answer 69

movements, balance, and muscle tone.

Question 70

pons

Answer 70

means “bridge,” relays information between the two regions of the cerebellum, and between the cerebellum and the medulla oblongata.

Question 71

medulla oblongata

Answer 71

onnection between the peripheral and central nervous systems. It controls involuntary muscle action and acts as the coordinating centre for the autonomic nervous system

Question 72

human brain can be divided into three main regions:

Answer 72

forebrain, the midbrain, and the hindbrain.

Question 73

Sympathetic nervous system

Answer 73

``` Prepares the body for stress Increases heart rate Decreases peristalsis Increases release of glucose Dilates pupils Relaxes bladder sphincter Increases blood flow to the skin Causes adrenal gland to release epinephrine ```

Question 74

Parasympathetic nervous system

Answer 74

``` Restores normal balance Decreases heart rate Increases peristalsis Decreases release of glucose Constricts pupils Contracts bladder sphincter Decreases blood flow to the skin Has no effect on adrenal gland ```

Question 75

Thyroid-stimulating hormone (TSH)

Answer 75

AP Thyroid gland Stimulates release of thyroxine from the thyroid Thyroxine regulates cell metabolism

Question 76

Adrenocorticotropic hormone (ACTH)

Answer 76

AP Adrenal cortex Stimulates release of hormones involved in stress responses

Question 77

Somatotropin (STH) or growth hormone (GH)

Answer 77

AP Most cells Promotes growth and cell division

Question 78

Follicle-stimulating hormone (FSH)

Answer 78

AP Ovaries, testes In females, stimulates follicle development in ovaries In males, promotes the development of sperm cells in testes

Question 79

Luteinizing hormone (LH)

Answer 79

AP Ovaries, testes In females, stimulates ovulation and formation of the corpus luteum In males, stimulates the production of sex hormone testosterone

Question 80

Prolactin

Answer 80

AP Mammary glands Stimulates and maintains milk production in lactating females

Question 81

Oxytocin

Answer 81

Posterior lobe Uterus, mammary glands Initiates strong contractions for childbirth Triggers milk release in lactating females

Question 82

Antidiuretic hormone (ADH)

Answer 82

Posterior lobe Kidneys Increases water reabsorption by kidneys

Question 83

Epinephrine | Norepinephrine

Answer 83

Adrenal medulla short term stress The blood vessels dilate, allowing more oxygen and nutrients to reach the tissues.

Question 84

Glucocorticoids (e.g. cortisol) | Mineralocorticoids (e.g. aldosterone)

Answer 84

``` Adrenal cortex long term stress Muscles, liver Converts fats to fatty acids to produce energy for the body - cortisol ``` Aldosterone increases sodium retention and water reabsorption by the kidneys, thereby helping to maintain body fluid level.

Question 85

short-term stress

Answer 85

Epinephrine Increases Mobilizes energy release from stored carbohydrates and fats Increases blood glucose and fatty acids Accelerates heart rate and breathing Glucagon Increases Converts glycogen to glucose Insulin Decreases Decreases the breakdown of glycogen in the liver

Question 86

Long-term exposure

Answer 86

Higher blood sugar Alters osmotic balance between blood and extracellular fluids; can lead to increased fluid uptake by the blood and increased blood pressure Increases water loss from nephron Increased blood pressure Can rupture blood vessels due to higher pressure Increases blood clotting Increased heart rate Can lead to higher blood pressure Can damage heart muscle

Question 87

Parathyroid hormone

Answer 87

Parathyroid gland Kidneys, intestines, bones causes the kidneys and the intestine to retain calcium, while promoting calcium release from bone.

Question 88

Thyroxine (T4) and triiodothyronine (T3)

Answer 88

thyroid cell metabolism regulate body metabolism and the growth and differentiation of tissues.

Question 89

Calcitonin

Answer 89

thyroid | the bone cells to lower the level of calcium ions found in the blood.

Question 90

estrogen and progestrerone

Answer 90

ovary developing follicle Causes the egg to mature (undergo meiosis) Thickens the lining of the uterus

Question 91

Testosterone

Answer 91

testes. developing sperm cells increases sperm production

Question 92

differnce betweem protien and steroid hormones

Answer 92

Steroid hormones are derivatives of cholesterol. -cortisol, testosterone omposed of complex, fused rings of carbon, hydrogen, and oxygen molecules. Steroid hormones are not soluble in water but are soluble in fat. Protein hormones include insulin and growth hormone. They contain chains of amino acids that vary in length. They are soluble in water. They bind at specific receptor sites