SAMPLE TEST QUESTIONS FROM CELL CYCLE 1.If there are 20 chromatids in a cell, how many centromeres are there? a.20 b.80 c.10 d.30 e.40

SAMPLE TEST QUESTIONS FROM CELL CYCLE 1.If there are 20 chromatids in the cell at metaphase, how many chromosomes are there in each daughter cell following cytokinesis? a.80 b.10 c.30 d.20 e.40

SAMPLE TEST QUESTIONS FROM CELL CYCLE 1.If a cell has 8 chromosomes at metaphase of mitosis, how many chromosomes will it have during anaphase? a.4 b.8 c.16 d.2 e.1

SAMPLE TEST QUESTIONS FROM CELL CYCLE During which phases of mitosis are chromosomes composed of two chromatids? a.From G1 of interphase through metaphase b.From interphase through anaphase c.From anaphase through telophase d.From metaphase through telophase e.From G2 of interphase through metaphase

CHAPTER 45: HORMONES AND THE ENDOCRINE SYSTEM

DAY 1

HORMONES Molecules secreted into extracellular fluid Circulates through blood and hemolymph Targets specific cells

2 CATEGORIES OF HORMONES Figure 45.5 (pg. 978) Water-soluble Cannot pass through cell membrane Lipid-soluble Able to pass through the cell membrane

3 GROUPS OF HORMONES Polypeptides Ex: insulin Water soluble Amines Ex: epinephrine, thyroxine Water soluble Steroids Ex: cortisol Lipid soluble

WATER SOLUBLE HORMONES Signal receptor on cell membrane Typical activities of water soluble hormones Activates enzymes Alter uptake/secretion of molecules Alter cytoskeleton

WATER SOLUBLE HORMONES Signal transduction : extracellular signal triggers a specific intracellular response Example: epinephrine (Figure 45.6) Secreted by adrenal gland Reaches liver cells, causes breakdown of glycogen within the cell Glucose is secreted into the blood stream

LIPID SOLUBLE HORMONES Activities: Causes a change in gene expression Hormone and intracellular receptor bind Complex moves into nucleus Alter transcription

NEGATIVE FEEDBACK OF HORMONES Most hormones follow a negative feedback loop Secretion of the hormone will cause a response which will reduce the stimulus which caused the secretion of the hormone

ANTAGONISTIC HORMONES Insulin and Glucagon Both are produced in the pancreas Endocrine cells called islets of Langerhans Alpha cells – synthesis of glucagon Beta cells – synthesis of insulin

INSULIN AND GLUCAGON Insulin : Released to increase uptake of glucose from the blood Lowers blood sugar concentration Glucagon : Released to promote release of glucose into blood Raises blood sugar concentration Figure pg. 983

DAY 2

IMPORTANT ENDOCRINE GLANDS (PG. 987) Hypothalamus Pituitary Anterior Pituitary Gland Posterior Pituitary Gland Thyroid Parathyroid Adrenal Gonads Pineal

HUMAN ENDOCRINE SYSTEM

HYPOTHALAMUS Integrates nervous system and endocrine system Located within the brain Initiates endocrine signaling in response to external stimuli Seasonal changes Mating

PITUITARY GLAND At base of the hypothalamus Anterior Pituitary – derivative of mouth during embryo development Regulated by hypothalamus Posterior Pituitary – extension of the hypothalamus Stores and secretes hormones from hypothalamus

POSTERIOR PITUITARY GLAND Oxytocin Positive feedback Regulate milk production Uterine contraction Mood and sexual arousal Antidiuretic hormone Blood osmolarity Kidney regulation Increases water retention within the kidneys Lowers volume of urine

ANTERIOR PITUITARY GLAND Hormone cascade pathways Hormones triggering other hormones Tropic hormones : regulates function of endocrine cells and glands Nontropic hormones

TROPIC HORMONES Follicle-stimulating hormone (FSH) Lutenizing hormone (LH) Both are produced in the gonads Adenocorticotropic hormone (ACTH) Steroid released from adrenal gland

NONTROPIC HORMONES Prolactin Mammals: lactation Birds: fat metabolism Amphibians: delays metamorphosis Thought to be conserved throughout evolution Melanocyte stimulating hormone (MSH) Skin pigmentation (amphibs, fish, reptiles) Neurons in the brain (mammals)

GROWTH HORMONE Anterior pituitary gland Targets liver Releases insulin-like growth factors (IGFs) Bone and cartilage growth Hyper-release – gigantism Hypo-release – dwarfism

DAY 3

THYROID HORMONE Regulates: Bioenergetics Maintain normal: Blood pressure Heart rate Muscle tone Digestive and reproductive functions 2 hormones: triiodonthyronine (T3), thyroxine (T4)

THYROID HORMONE Hyperthyroidism High body temperature Excessive sweating Weight loss Irritability High blood pressure Hypothyroidism Weight gain Lethargy Intolerance to cold For proper thyroid function, need iodine (iodized salt)

PARATHYROID HORMONE Regulates Ca2+ levels Release of parathyroid hormone raises Ca2+ levels within the blood Breakdown of bony matrix Vitamin D – needed for proper Ca2+ absorption Active form of Vit.D from kidneys triggers uptake of Ca2+ from food in intestines Calcitonin – inhibits bone resorption (breakdown of bone to release calcium)

ADRENAL HORMONES Adrenal glands 2 parts: Adrenal cortex Adrenal medulla

ADRENAL HORMONES Norepinephrine Epinephrine Both increase breakdown of glycogen in liver, skeletal muscles Promote release of glucose by liver cells, fatty acids by fat cells Increases heart rate, dilates bronchioles

ADRENAL HORMONES Steroids from adrenal cortex Corticosteroids : Glucorticoids Mineralcorticoids

GLUCORDICOIDS Glucose metabolism from noncarbohydrate sources (skeletal muscles) Cortisol – skeletal muscle breakdown Glucose to liver and kidneys Anti-inflammatory effect NSAIDs have similar effect but without the negative side effects of steroids

MINERALOCORTICOIDS Salt and water balance Aldosterone Stimulate kidney to balance water and sodium balance

GONADS Female is “default” in mammals Testosterone production triggers male development Lower voice, increase muscle mass, bone mass Testes produce androgens

OVARIES Production of Estrogens (estradol) Female reproductive development Secondary sex characteristics Progestines (progesterone) Uterine maintenance Synthesis of androgens, estrogens, progestines – regulated by FSH, LH

MELATONIN Synthesis in the pineal gland Near center of the brain in mammals In lower vertebrates, has light receptors – closer to surface of body Circadian rhythms, night/day