Human Biology Task 1 Flashcards
What do hormones affect
all cells in the body
a particular group (target cells)
a particular organ (target organ
Define Hormones
chemicals, secreted by endocrine glands, that are transported throughout the body in the blood.
- change the functioning of cells by changing the type, activities or quantities of proteins produced
Three types of hormones
Protein hormones
- Made of proteins
- E.g. Insulin
Amine hormones
- Made of single amino acids
- E.g. Adrenaline
Steroid hormones
- Made of lipids
- E.g. Cortisol
5 features of water soluble hormone
- Amine(frm singe amino acid) + protein hormones(frm multiple amino acids)
- Hydrophobic – cannot diffuse through membrane. as the phospholipid tails repell it.
- Attach to receptor proteins in the membrane of the target cell.
- Causes secondary messenger substance to diffuse through the cell and activate particular enzyme
- Quick response, short lasting effects
4 Features of lipid soluble hormone
- Steroid hormones(frm cholesterol)
- Diffuses across membrane (hydrophillic) and combines with receptor inside the cell (nucleus or cytoplasm)
- Hormone-receptor complex binds to section of gene activating/inhibiting transcription and protein synthesis (gene expression).
- Slow to have effect, long lasting.
Two types of glands 3,2
Exocrine glands
- secrete hormones into a duct that carries the secretion to the surface/body cavities.
- E.g. Sweat glands, salivary glands.
Endocrine glands
– secrete hormones into extracellular fluid which passes into capillaries to be transported around the body.
Describe hypothalamus?
contains neurosecreotry cells
- releasing/inhibiting factors travel thru blood vessels sent to ant.pit
- secretes oxytocin and ADH to post.pit
- regulates many of the body’s basic functions. E.g. body temperature, water balance, heart rate.
- mainly acts through the pituitary gland
- produces hormones which travels by blood or along nerve fibres to Pituitary gland
PITUITARY GLAND 4
- Vital to normal functioning.
- Known as ‘master gland’ due to the pituitary hormones often regulating activity of other endocrine glands.
- Some hormones made in hypothalamus are secreted by pituitary gland.
- all hormones secreted are protein
Anterior lobe (pituitary) secretes…1,4,4,3,3,5
Actually produces and secretes
Follicle Stimulating Hormone (FSH)
- targets ovaries/testes
- Female: development of follicles
- Male: sperm production
Leutinising Hormone (LH)
- targets ovaries/testes
- Female: triggers ovulation
- Male: secretion of sex hormones
Growth Hormone (GH)
- targets all cells
- Body growth and increase protein synthesis rate
Thyroid Stimulating Hormone (TSH)
- targets thyroid gland
- Production and release of hormones
Adrenocorticotropic Hormone (ACTH)
- targets adrenal cortex
- Production and release of hormones
Prolactin
- targets mammary glands
- Initiate and maintain milk secretion
Posterior Lobe 2,5
Communicates via nervous impulses
Does not produce hormones, only stores and secretes
Oxytocin
- targets Uterus and mammary glands
- Uterine muscle contractions and milk let-down
Antidiuretic Hormone (ADH)
- targets Kidneys
- Fluid retention
Thymus 3
Thymosin(protein)
- T-Lymphocytes
- Influences the maturation of T-lymphocytes
Pancreas 3,3
Glucagon
- targets Liver
- Raises blood sugar by stimulating glycogen breakdown
Insulin
- targets Liver, muscle and fat stores
- Lowers blood sugar by promoting glucose to turn into glycogen
(Protein)
Testes 5
Androgens (e.g. Testosterone)
(Steroid)
- targets Many tissues
- Stimulate sperm production.
- Growth of skeletal muscle.
- Development/maintenance of male sex characteristics
Ovaries 4,4
Oestrogens
- targets Many tissues
- Development of Female Characteristics.
- Regulates the Menstrual cycle
Progesterone
- targets Uterus and Mammary glands
- Regulate menstrual cycle/pregnancy.
- Prepares mammary glands for milk secretion.
(Steroid hormone)
Adrenal Medulla 3,3
Adrenaline
- targets Most cells
- Fight-or-Flight response
Noradrenaline
- targets Most cells
- Similar effects (increases heart rate)
(Amine hormone
- both increase metabolism